I say "upsets" because Alireza Firouzja was the higher seed. But in this match, there was no indication that he was Vladimir Fedoseev's superior. Fedoseev led almost from start to finish, and it was only a near-epic collapse at the end of regulation that allowed Firouzja to force overtime. Fedoseev was up by two points with less than four minutes left, and could have played on in a queen vs. queen ending to run off at least another 30-60 seconds. Then he was winning the next game, but collapsed and wound up losing with just a few seconds left on the clock. That forced one last game, and there was no need for Fedoseev to lose that one either, but he did.
To Fedoseev's great credit, he recovered. The overtime was a best-of-four at the 1'+1" time control, and would have been followed by an Armageddon game, if necessary. The first game was drawn, and then Fedoseev won the second game. Firouzja continued to demonstrate his own resilience, striking back in game 3, but in the final game it was Fedoseev who had the last laugh, winning the match 15-14. Very well done!
The next match on the event schedule is tomorrow - Sunday - between Wesley So and the young Uzbek GM Nodirbek Abdusattorov. The action starts at 12 ET/18:00 Central European Time.
Event page here.