It was a great event and Grand Prix series for Hikaru Nakamura. He won the series and qualified for the Candidates, but a loss to Wesley So in the rapid playoff today means that his compatriot won this particular Grand Prix event while knocking Nakamura into second on the rapid rating list - he had passed Magnus Carlsen earlier in the event to take first place. (He remains in first place in blitz, though, with Carlsen second and So in third.)
To the chess: they drew their classical games, and moved on to a rapid tiebreak. The first game of the tiebreak was also drawn, and then So won the second and final game of that playoff, grinding Nakamura down from the white side of a 5.Re1 Berlin. Here's the game, with my notes.