Wesley So's 48-game unbeaten streak at the U.S. Championships ended in shocking fashion when he lost to Sam Sevian in the final round. Sevian sat in last place heading into the game. So needed just a draw to secure the title outright, but he collapsed against the underdog.
Fabiano Caruana pounced on the opportunity. He defeated Awonder Liang in the final round and caught So at the top of the standings, forcing a playoff.
The championship will be decided entirely in rapid and blitz formats. The first tiebreak consists of two rapid games at 15+10. If that doesn't break the deadlock, Caruana and So play two more rapid games. From there, they move to blitz matches at 5+2, up to two games each. Should they remain tied after all that, the arbiter will determine the next step.
The format gives both players a chance to settle matters quickly without returning to classical chess. Caruana enters the playoff hot, while So must shake off the mental weight of his loss to Sevian. Rapid play favors strong nerves and practical decision-making over pure calculation. Both players excel in these formats, so the championship remains completely open.