It seems the good folks at the St. Louis Chess Club are determined to keep their audience entertained, so we have not just two matches - the finals for the championship and the women's championship - but four, as the semi-final losers in each bracket face off to settle the third and fourth places.
In the match that really counts, Gata Kamsky ended Yuri Shulman's long undefeated streak, pulling out an ending with the aid of the old psychological axiom "Do not hurry". In positions where your opponent is worse and unable to do much (if anything) in a positive direction, it's often a good idea to meander a bit, to tack back and forth, to repeat moves and engage in other temporizing activities. This policy often bears fruit, quite often by giving the opponent the chance to self-destruct.
In this game, the moment-of-suicide was 44...Be3. It wasn't at all obvious how Kamsky would make progress after 44...Rg2 (45.Kd2 Rg3), but Shulman thought he would really fix his problems with 44...Be3. Unfortunately, this was a big error: Kamsky switched the rook around to d3, forcing an exchange of rooks. After that Kamsky's extra pawn was enough for an easy win in the bishop ending. Shulman must therefore win tomorrow to stay in the match.
In the women's championship, gambit-lover Tatev Abrahamyan went for a modern version of the Milner-Barry Gambit against Anna Zatonskih's French (with 9.Nbd2 rather than the old-fashioned 9.Nxd4 Qxd4 10.Nc3 and so on). I'm not sure she got much out of it, but when Black played 17...Bb5 (rather than, say, 17...Rc8) it looked like White could have obtained a pleasant initiative after 18.Bxb5 Qxb5 with 19.Nd4 followed by 20.Rac1. Instead, Abrahamyan chose 19.Qf4, and this didn't seem as effective. Zatonskih kept her extra pawn and may have had some chances to consolidate it later. If so, she failed to take advantage, and by keeping as active as possible Abrahamyan managed to scrape out a draw.
In the 3rd-4th match games, Shankland-Hess was drawn in a Catalan that seemed a bit easier for Hess, while Krush won fairly easily against Baginskaite, despite having Black. Baginskaite's opening was rather odd, and the weaknesses created in the early middlegame came home to roost later on, as Krush finished her off with a nice flurry of tactics.