Indian Grandmaster P Harikrishna claimed a share of the top position with Armenian GM Levon Aronian after posting two wins and a draw in three rounds of rapid competition in the St Louis Rapid and Blitz online chess tournament.
The India No. 2 started with a win over US Grandmaster Leinier Dominiguez, before settling for a draw with Iranian prodigy Alireza Firouzja in games played late on Tuesday.
In the third round, Harikrishna pulled off a victory over experienced Russian Alexander Grischuk in 41 moves.
World champion Magnus Carlsen, the favourite to win the title, was fifth with three points.
After a win over Hikaru Nakamura in his opener, the Norwegian went down to Russia's Ian Nepomniachtchi in the second round. A draw with Wesley So in the third left the world no.1 in fifth spot.
Harikrishna, coming from a good showing in FIDE Online Olympiad, outwitted the American in 51 moves with black pieces, to begin his campaign in the elite 10-player event.
The Indian ace will face Nepomniachtchi in the fourth round, followed by games against Aronian and Carlsen late on Wednesday.
In each rapid game, a win is worth 2 points, and a draw is worth 1 point, while in the blitz game, a win is worth 1 point and a draw fetches half a point.
The 10 players are competing for a US$250,000 prize fund in nine rapid games and eighteen blitz games over five days of play.
The tournament hosted by US-based St Louis Chess Club concludes on September 19.
Standings after three rounds:
1. Lev Aronian and Harikrishna 5 pts; 3. Ian Nepomniachtchi and Wesley So 4 pts; 5. Magnus Carlsen 3 pts; 6. Hikaru Nakamura, Leinier Dominiguez, Alireza Firouzja, Jeffery Xiong 2 pts; 10. Alexander Grischuk 1 point.