Liem, with an Elo rating of 2,741, surprised everyone when he defeated Ding (Elo 2,736) after 62 moves.
The game lasted nearly five hours and at the end, Ding covered his face with both hands, sighed, then stopped the clock and shook hands with Liem.
Vietnam's number one player did not show too much emotion as his face relaxed, looking relieved and leaning back in his chair. This was the most watched game in round six of the tournament, taking place at the main table, where only camera angles from the chessboard were directed towards the player's face.
Liem, playing black, only had a small advantage from the endgame with the rook and the bishop, but time was on his side. Ding made some weak moves when there were only a few seconds left on the clock. Taking advantage of the opportunity, Liem gradually converted it into a winning game for him. Ding tried to hold on for about 20 more moves before surrendering.
Liem's victory was important as it set the score at 2-2 for the Vietnam men's team. In the three games that ended previously, Nguyen Ngoc Truong Son (Elo 2,633) quickly drew against Wei Yi (2,762) after 15 moves, while Tran Tuan Minh (2,434) lost to Wang Yue (2,637) and Le Tuan Minh (2,564) had a draw with Yu Yangyi (2,703).
The four Chinese players have an average Elo of 2,710, compared to Vietnam's 2,593. All four Chinese grandmasters have been in the world's top 10, something no Vietnamese player has ever done in history.
In the previous two matches, Liem and his teammates also beat defending champion Uzbekistan and 11th seed Poland.
"Vietnam created a third consecutive earthquake when they drew against China," the International Chess Federation (FIDE) commented.
Liem once again reached the peak of his career, with a real-time Elo of 2,749.9 and moved to 12th in the world. He is only 1 Elo away from the world's top 10. The 33-year-old player also maintained an unbeaten record every time he played against Ding in standard chess, with two wins and six draws.
Ding is considered the "chess king", an unofficial title given to the world's standard chess champion. But since his world title win, Ding's form has declined. He has fallen out of the world's top 20, to 22nd. In the first four games of the tournament, the 30-year-old has drawn all of them. He only needed a draw in the fifth game to help China maintain their winning streak but failed.
With five wins and one draw, the Vietnam men's team are having the best start ever at a Chess Olympiad. With 11 points, they are only behind the second seed India, the only team to have won all games so far in the open group.
The women's team lost 1.5-2.5 to the sixth seed Azerbaijan. They have earned eight points so far, placing 23rd. India are leading both the open and women’s table.
The 2024 Chess Olympiad is taking place in Budapest, Hungary from Sept. 10 to 23, marking the 100th anniversary of the tournament. The tournament is considered the Olympics of the chess world, gathering most of the world's top players.