Fabiano Caruana struck first in the title match of the Grand Chess Tour Finals, defeating Praggnanandhaa Rameshbabu in Tuesday's opening classical game to collect six points.
Pragg, playing black, emerged from a strategically complex Italian Opening in good shape. Caruana reached a middlegame with bishop against knight, but there was no substantial advantage for White and the position remained roughly balanced into the later stages.
The turning point came on move 28. Praggnanandhaa had an opportunity to steer the game towards a draw but instead chose 28...Rc8?, a tactical error that lost a pawn immediately. Caruana took advantage of the mistake and converted without allowing his opponent back into the game.
The result gives Caruana a six-point lead, though the scoring system leaves plenty of room for a comeback. A rapid win is worth four points, so Praggnanandhaa does not necessarily need to force matters immediately in Wednesday's second classical game.
Caruana is attempting to retain the GCT Finals title, while Pragg is seeking his first triumph in the event. The second classical game will be played on Wednesday, before the rapid and blitz section concludes the match on Thursday.

Defending champion Fabiano Caruana scored a crucial victory with the white pieces on Tuesday | Photo: Lennart Ootes

Praggnanandhaa Rameshbabu | Photo: Lennart Ootes
Vincent Keymer and Wesley So shared the six available points in the first classical game of the third-place match after a complicated London System ended in a draw.
The game developed unusually, with neither player castling at any stage. The middlegame contained several sharp possibilities, particularly around the potential 20.g6 break, which could have led to major complications involving an exchange sacrifice.
Here Keymer continued with 20.Qb6, and there followed 20...Nd6 21.Bxf5 Nxf5, and the queens were traded four moves later, leading to a balanced, simplified position.
Instead, the German GM could have gone for the sharp 20.g6!?, and after 20...Bxg6 White has 21.Rxg6 fxg6 22.Bxe4 dxe4 23.Ne5, with great compensation for the exchange.
The quieter path which the players followed in the game eventually led to a rook ending in which neither side could make meaningful progress, and the players agreed to a draw.
After a demanding month of elite competition in Saint Louis, all four players still have two days of play remaining. The stakes are high as the GCT season comes to an end.

Wesley So and Vincent Keymer right after signing a draw | Photo: Lennart Ootes

Vincet Keymer | Photo: Lennart Ootes