I don't recall exactly how many games Wesley So had played without a loss in Classical chess - it was 50-something, I think - but that streak is at an end. His game with Shakhriyar Mamedyarov had been approximately equal most of the way, and after 38 moves it was still equal. Had So played 39.gxf3 any result would have been possible, with a draw the likeliest and most correct option. Instead, he uncorked 39.Qxf3+??, Mamedyarov replied with the obvious 39...e4, and So resigned. It's hard to figure out what he missed, as ...Qxc4+ is an obvious crusher*. Maybe it was time trouble, or a moment of blindness. Whatever the case, it was a fantastic run, and now it's time for him to start building a new streak.
The day's other winner was Pavel Eljanov, who won smoothly against Teimour Radjabov in a knight vs. bishop ending. In the draw department, Vladimir Kramnik was better forever against Radoslaw Wojtaszek but couldn't put him away; it seems this is mostly due to great defense by Wojtaszek rather than Kramnik's having missed something concrete. Veselin Topalov had an advantage against Michael Adams that gradually evaporated after the latter's good defense, and Sergey Karjakin drew with Pentala Harikrishna in a game that was pretty level throughout.
Round 2's pairings: Kramnik - Radjabov, Harikrishna - Eljanov, Mamedyarov - Karjakin, Adams - So, and Wojtaszek - Topalov.
* A Wesley [So] crusher? Apologies to GM So, fans of the "Star Trek: The Next Generation", and to pun haters everywhere. (But not that sorry.)