Revisiting Magnus Carlsen’s 125-game unbeaten streak

On move 63 of their game at Norway Chess 2020, Magnus Carlsen resigned against Polish Grandmaster Jan-Krzysztof Duda.

Carlsen had the black pieces and answered Duda's 1. e4 with the Caro-Kann. After Duda castled queenside on move 11, Carlsen gradually lost his grip on the position, handing Duda several chances to take over. On move 19, Duda took one. Carlsen gave up a rook for a bishop, a sacrifice the engine rated as roughly equal but one that left him with a position that was very difficult to play. By move 22, Duda had a clear advantage. He nursed it for another 40 moves and converted.

It was a fine win in its own right. But it also ended the most remarkable unbeaten run in modern chess: 125 classical games without defeat, stretching across 802 days.

Long unbeaten streaks are not unusual at the top level, where draws are common. What sets this one apart is the opposition. Over the 125 games, Carlsen's opponents averaged 2744. As of 2026, excluding Carlsen, only 12 players in the world are rated above that figure.

The run began in Biel, in July of 2018.

Biel, 2018

Biel 2018 was an uncharacteristically poor event for Carlsen. The field was strong, including Shakhriyar Mamedyarov, Peter Svidler and Maxime Vachier-Lagrave, but nothing a player of his level would usually struggle with.

He beat David Navara in round one and Vachier-Lagrave in round two, then drew Svidler, Nico Georgiadis and Mamedyarov. At the halfway mark he was level with an in-form Mamedyarov. A draw with Navara in round six, while Mamedyarov beat Georgiadis, left him trailing. In round seven he drew Vachier-Lagrave as Mamedyarov beat Navara. Both drew in round eight, and in round nine they met.

Carlsen needed a win. Instead, after a precise English setup, he slipped with Qf8 on move 26, giving Mamedyarov an advantage of around a pawn. Mamedyarov held it for another 30 moves and won on move 57, sealing the tournament.

In the final round, Carlsen beat Georgiadis. At the time it meant nothing. It was game one of 125.

Long unbeaten runs have been recorded before. Between 2004 and 2005, Sergei Tiviakov went 110 games unbeaten against opponents averaging 2476. Between 2017 and 2018, Ding Liren went 100 games unbeaten against a far stronger average opposition, in the 2700s.

After the win over Georgiadis, nobody was thinking about either record. The focus was the 2018 Sinquefield Cup.

Sinquefield Cup, 2018

There was nothing spectacular about Carlsen's Sinquefield Cup, and that was the point. He drew Vachier-Lagrave in round one, beat Sergey Karjakin in round two, drew the next six games and beat Hikaru Nakamura in round nine to share first with Fabiano Caruana and Levon Aronian.

The field averaged 2799.3. And although Carlsen did not run away with it - he was simply impossible to get past. Tournaments like this one explain how the streak went on for so long.

European Club Cup, 2018

The European Club Cup was the calm before the world championship match. After sitting out round one, Carlsen beat Vladimir Potkin and then drew Radosław Wojtaszek, Alexander Donchenko, Mamedyarov, Ding and Svidler.

The Ding game was the closest call. Carlsen allowed the strong ...Nxg4 on move 24 and spent 21 moves in a worse position before holding the draw. His other games were comfortable.

The 2018 World Championship

Carlsen's next opponent was Caruana, in the world championship match. Caruana was rated 2832, just three points below Carlsen.

The pair drew all 12 classical games, the first time a world championship match had produced no decisive classical result. Carlsen won the title on rapid tiebreaks, taking all three games.

Caruana had very few real winning chances. In game six he briefly had a winning position, for a single move, but Carlsen defended with great precision. Twelve classical games against an opponent rated 2832, without a loss, sent a clear message to the rest of the field.

Tata Steel, 2019

Tata Steel is one of the most prestigious events on the calendar. Its fields usually include a few wildcards selected for nationality or age, which brought the average rating down to a still formidable 2753.

Carlsen made it look easy. After draws with Ding, Ian Nepomniachtchi, Vidit Gujrathi and Vladimir Kramnik, he beat Jorden van Foreest in round five and Mamedyarov in round six, avenging Biel with a win on move 51. He drew Vladimir Fedoseev, then beat Richard Rapport in 41 moves with a crushing mating attack. Sam Shankland held him as black in round nine.

His draws were controlled throughout. Against Fedoseev, the evaluation tipped slightly in his opponent's favour, but never by more than about a third of a pawn.

He beat Viswanathan Anand in round 10, drew Teimour Radjabov, beat Duda in round 12 and drew Anish Giri in the last round. He won on 9/13, half a point ahead of Giri.

Across the whole tournament, Carlsen never spent a move a full pawn worse. He was never even half a pawn worse.

The streak now stood at 41 games, the point at which most unbeaten runs end. By late 2025, the only active streak with comparable opposition was Daniil Dubov's run of 45 games. After Tata Steel 2019, Carlsen's was already the most significant active streak in chess.

Gashimov Memorial, 2019

The Gashimov Memorial in Shamkir averaged 2778, comparable to a field of ten players at the level of 2026 Candidates winner Javokhir Sindarov.

Carlsen drew Radjabov in round one, then beat Anand in round two and Navara with black in round three. After draws with Veselin Topalov, Mamedyarov and Ding, he beat Giri with white, crushed Karjakin with black and beat Alexander Grischuk in the final round.

He finished on 7/9, two points clear of Ding and Karjakin. He did not spend a single move in a worse position. His worst position of the tournament was, effectively, move one of each game he played as black.

Grenke Classic, 2019

Grenke also mixes elite players with rising talent. In 2019 that meant a 14-year-old Vincent Keymer, and an average field rating of 2725.

Carlsen beat Keymer in round one, grinding him down in an 81-move endgame, then beat Francisco Vallejo Pons. He drew Anand, Caruana and Arkadij Naiditsch, then won his last four games against Georg Meier, Aronian, Svidler and Vachier-Lagrave. He won on 7.5/9, 1.5 points ahead of Caruana.

The one wobble came in the Keymer game. After 29. g5, the teenager briefly had an advantage of about a pawn.

By this point, Carlsen's running total of moves spent in a worse position stood at 22.

Norway Chess, 2019

From here, Carlsen would go roughly another year without defeat.

Norway Chess fields are consistently elite. The 2019 edition averaged 2783. That year, drawn classical games went to an Armageddon playoff. Only the classical games count towards the streak, and the format encouraged more classical draws than usual.

Carlsen drew Anand in round one. His round-two draw with Aronian was the first serious threat to the streak. After 14...g5, Aronian's advantage reached a full pawn, and he held it until move 54, when he pushed his h-pawn, overlooking that Carlsen's later Ra1 would secure a straightforward draw. Carlsen was worse for 40 consecutive moves.

The scare seemed to sharpen him. He beat Grischuk in 34 moves with white, drew Mamedyarov, Vachier-Lagrave, Ding and Wesley So, beat Yu Yangyi in round eight and drew Caruana in the final round. With his Armageddon results, he finished first.

The Aronian game showed Carlsen could be caught, and that any great streak needs some luck. Aronian deserves credit too, as one of the finest players of his era. His running total of moves in a worse position rose to 62.

Grand Chess Tour Croatia, 2019

The Grand Chess Tour, founded in 2015, brought another ferocious field, averaging 2779.

Carlsen set the tone in round one, beating Giri with black in 23 moves. He drew Anand, Caruana, Mamedyarov and Karjakin, then beat Nakamura with white, Nepomniachtchi with black and Ding. Draws with Aronian and So followed, and he closed with a win over Vachier-Lagrave.

He won outright on 8/11, a point ahead of So, and never spent a move in a worse position.

Sinquefield Cup, 2019

A year after it began, the streak returned to Saint Louis. The 2019 Sinquefield Cup averaged 2779. Carlsen arrived 79 games unbeaten, and questions were growing about Tiviakov's 110 and Ding's 100.

He drew his first nine games, an unusually passive start that hurt his tournament chances. Wins over So in round 10 and Vachier-Lagrave in the last round forced a rapid playoff with Ding, which Ding won.

Carlsen again never spent a move in a worse position in the classical games. The streak reached 90, ten short of Ding's record.

Grand Swiss, 2019

The 11-round FIDE Grand Swiss on the Isle of Man would decide whether Carlsen reached 100.

When Tiviakov reached 100 games unbeaten in 2005, he admitted the pressure had affected him: "It became difficult for me to sleep since I started to believe in my invincibility." A long streak creates a tension of its own. The instinct is to protect it, but sometimes a tournament demands a win rather than a draw.

As an open Swiss, the event also offered Carlsen some weaker early opponents. He beat Yuriy Kuzubov in round one, though after Qb4 on move 31 he was briefly worse by about 1.4 pawns. As against Keymer, the trouble came against a much lower-rated opponent.

He drew Alexey Sarana and former FIDE world champion Rustam Kasimdzhanov. Against Vladislav Kovalev in round four he was in real danger. After Rad8 on move 23 he allowed f4, then worsened his position by trading a knight for a bishop. By move 26 he was three pawns worse. Kovalev's hasty Nxc5 on move 30 let him escape with a draw.

Carlsen then beat Surya Ganguly and Alexei Shirov, and drew Kirill Alekseenko, Wang Hao and Caruana.

In round 10 he met Maxim Matlakov, rated 2688. It was game 100. Matlakov chose the Slav Defence but repeatedly allowed Carlsen inroads, and by move 26 Carlsen was a pawn better. The advantage kept growing. By move 80, Carlsen had reached a winning queen-versus-rook endgame.

In the final round, a precise 34-move draw with Aronian took him to 101 games, past Ding's record.

Despite only placing joint 3rd, he spent just 13 moves in a worse position across the event.

London Chess Classic, 2019

Tiviakov's 110 still stood. The London Chess Classic, the Grand Chess Tour final, combined two classical games per match with faster time controls, so Carlsen played only four classical games.

He drew Vachier-Lagrave twice in classical before losing to him in the faster games. In the third-place match against Aronian, he won one classical game and drew the other. In that draw he was again worse against Aronian, for 19 moves between moves 15 and 34 and for six more later on.

He did not win the Grand Chess Tour, but he added four games to the streak.

Tata Steel, 2020

Carlsen arrived at Tata Steel 2020 with two more wins from the Norwegian league, over Skrondal and Tryggestad, both rated around 2470. Tata Steel would decide whether he could pass Tiviakov.

He opened with seven draws: Giri, Yu Yangyi, Jeffery Xiong, Van Foreest, Daniil Dubov, Caruana and Anand. He beat Nikita Vitiugov in round eight, then Alireza Firouzja and Kovalev, before drawing Duda, Vladislav Artemiev and So.

Caruana won the event with a superb 10/13, but Carlsen broke Tiviakov's record along the way. Again, he never spent a move in a worse position.

Norway Chess, 2020: the end

The final stretch of the streak ran into Norway Chess 2020.

The move-by-move tally helps explain why it ended. At the Grand Swiss and London Chess Classic, Carlsen had been visibly out of form, and those two events accounted for roughly a third of all the moves he spent in a worse position. Opponents had reason to believe they could take points from him.

Before Norway he added a win over Manuel Ramirez, rated 2462, in Norway's Østlandsserien. At Norway Chess he drew Aronian without ever being worse, drew Firouzja and beat Aryan Tari, despite being worse between moves 18 and 23 until Tari's 23. Nh5. He beat Caruana in round four.

In round five, Duda ended it after 125 games.

Carlsen won round six, drew round seven and won rounds eight and nine before losing again, this time to Aronian, who finally got the win against him.

The numbers

Across the 125-game streak, Carlsen spent a total of 105 moves in a worse position, defined here as an engine evaluation of at least a pawn in his opponent's favour. That is about 1.9% of all the moves he played. For the remaining 98.1%, he was equal or better.

It is easy to dismiss a long unbeaten run at elite level. Roughly 60% of games between super grandmasters end in draws, and the best player of his generation might be expected to avoid defeat for long periods.

But 125 games against an average opponent rated 2744, while worse for fewer than two moves in every hundred, is a different thing. For most of that run, Carlsen was not only unbeaten. He was almost never under threat.