It was a great day for the American players, who rolled on to victory. Hikaru Nakamura was always going to win against Veselin Topalov, entering the final day with a big lead and an overwhelming favorite in the blitz. To no one's surprise - including Topalov's - he finished like a hammer, winning nine games and drawing three. The scoring in the blitz was 2-1-0, so he won the session 21-3 and won overall by a ridiculous 61.5-30.5 margin. All the matches have a $100,000 prize fund split 60-40, so Nakamura won $60,000 to Topalov's $40,000.
In the other two matches, the Americans continued the comebacks they had started at the end of day 3. Fabiano Caruana had won three games followed by a draw at the end of the previous day to close to within four points, and on day 4 he won, drew, and won again to equalize the scores. Having done so, Grischuk enjoyed his one bright spot when he won the fourth game - and even that took a lot of help: Caruana made a fingerfehler in the opening to lose a pawn, and when Caruana fought back to a drawn position he made two further errors to lose the game. But that was the end of his good news: in the last eight games the pattern kept repeating: a draw followed by a Caruana win. In all, Caruana won six games, lost just one, and drew five. He won the session 17-7 and the match 49-43.
Wesley So likewise continued his great comeback. He had won the last three games on day 3, and although he was still down seven points he too overcame his deficit. He won his first two games, drew, and won two more games to take the lead. The rest of the way the play was closer, but So never surrendered his lead. Overall he went +7-2=3, winning the section 17-7 and the match 47.5-44.5.
Finally, the world champion proved his greatness yet again. Magnus Carlsen dominated Ding Liren in the g/20 portion of the match, winning three games and drawing three. As you may recall, Carlsen led 12.5-7.5 after the first day, and with each of the 20-minute games weighted on a 4-2-0 basis he took day 2 18-6 and leads the match 30.5-13.5 going into the 10-minute games, which will start momentarily.
Congratulations to the Americans...and probably to Carlsen too, barring a quasi-miracle.