The playoff is over, and Wesley So has won the 2017 U.S. Championship. He defeated Alexander Onischuk 1.5-.5 in a pair of tiebreak games, winning the first with White and barely drawing the second with Black. In the first game, Onischuk played very sharply, sacrificing a couple of pawns for activity. In the short time controls (G/25, plus a five second time delay before each move) he didn't have enough time to work through the complications and maintain his activity, and So managed to take over and win pretty smoothly. In the second game Onischuk managed to reach a middlegame with two bishops against two knights, and while in theory the position was equal due to the knights' outposts, maintaining them was a difficult task. Onischuk outplayed the world's #2 and achieved both a winning position and a big time advantage, but couldn't figure out how to put him away. His best opportunity began with 41.Bd5+; missing that chance, the advantage started to slip away, bit by bit, and in the end, with both players almost out of time, So drew by perpetual.
Congratulations to Wesley So!