Correct play was the watchword for round 1, as all five classical games were drawn. No one was in serious trouble in any of the games, though Viswanathan Anand experienced some pressure against Magnus Carlsen and Alexander Grischuk had some small chances against Levon Aronian. All five pairings went to Armageddon games, and all five finished with a winner - the player with the white pieces, in four of the games.
Carlsen won easily against Anand, thanks to his bishops and much better pawn structure. The losing move, at least practically speaking, came as early as move 12, when Anand played 12...dxe5 rather than the dynamic 12...Ne4. There were some inaccuracies along the way - not surprisingly, given that it's essentially a slow blitz game (White gets 10 minutes, Black 7, with no increment until after move 61) - but Carlsen generally played well and Anand eventually cracked under White's long-term pressure.
Shakhriyar Mamedyarov's win over Fabiano Caruana was similar in terms of the plot line: much better right out of the opening, he maintained the advantage for a long time, had some stumbles, but his opponent was unable to take advantage and eventually lost.
Ding Liren demolished Wesley So with a kingside attack in a Semi-Tarrasch. As far as the opening was concerned, So was fine, but in the context of a blitz game he was unable to cope with his opponent's attacking initiative.
The general whitewash was interrupted in the game between Maxime Vachier-Lagrave and Yu Yangyi. MVL enjoyed a small but enduring edge, which had largely dissipated after Yu's 24...Re8. If he wanted to keep squeezing he should traded on e8, played 26.Qe3, and then pushed the g-pawn. Instead, he kept the rooks on with 25.Rf4 and then played 26.g4 followed by 27.g5. In this case it was self-destructive. Black's rook benefited from its uncontested possession of the e-file, the queen penetrated to a1, and all White's pawn pushed achieved was a weakening of his own structure and a loss of king safety. After this Vachier-Lagrave was in big trouble, and soon lost. (Given the Armageddon format, he still would have "lost" even with a draw, but his position was so bad that Yu was unlikely to extend that courtesy.)
Finally, Levon Aronian and Alexander Grischuk played an up-and-down game that was decided on the clock. Early on Grischuk had a decisive advantage on the board, and later it was Aronian who was winning on the board. By the end the position was equal, and in the fight to bash out enough moves to reach move 61 it was Grischuk who first ran out of time.
The games (without notes) are here; these are tomorrow's pairings: