Two excellent semifinal matches were contested, with both taking the full four games of the second mini-match and one going to Armageddon. For world champion Magnus Carlsen, things went comparatively smoothly. He won the very first game of the day, with Black, in excellent style. He was very close to winning game 2 as well, and may have been winning at one point. Aronian found an excellent defense, however, and saved a difficult ending by the skin of his teeth. Perhaps buoyed by his narrow escape, he took the upper hand in the third game, and was probably winning that one. Unfortunately for him, his 25th move was inaccurate (25.Ne4 was better) and his 27th a mistake (the multipurpose 27.Qd3 was better, blocking the d-pawn and helping protect the kingside pawns). After that, Carlsen was fine, and the game drifted to a draw. Finally, game 4 was a nervy affair. First Carlsen was better, but then he lost control in a wildly complicated middlegame. Had Aronian played 35...Rxa8 he would have had a winning advantage (the key point was that after 35...Rxa8 36.Rxa8+ Kh7 37.Ra7 Black has 37...Qd4, maintaining what should be a decisive material plus). The game remained complicated for a few more moves - though never standing in Aronian's favor - until serious errors on moves 41 and especially 42 gave Carlsen a winning advantage he soon converted.
If that match could have gone either way, the same could be said, in spades, for the war between Vladislav Artemiev and Alireza Firouzja. Game 1 finished in a draw, but Firouzja was winning until the mistaken 42.f4, allowing Black to swap off a couple of pawns and to activate his king to draw a pawn down ending. There was no escape for Artemiev in the second game. Despite having the white pieces, he was soon in trouble, and Firouzja never gave him a chance to survive. For the first time in the overall match, Firouzja had the lead, and having gone undefeated since his loss in the first game of the first mini-match he had completely taken over the initiative. So between that, and his possession of the white pieces in game 3, you'd think this would be his chance to bring the match to a close. An understandable thought, but a mistaken one. Artemiev was better from the jump, and although his technique lapsed at a certain point he dominated most of the game and was a deserved winner. Now he had the momentum, and had a winning position in game 4...but it finished in a draw: on to the blitz tiebreaks.
Both of those games finished in draws. Firouzja had the more comfortable play in both games, but no wins were missed and the results were well-earned by both players. On to Armageddon. Artemiev chose to have White, which is, I think, the correct decision since the Meltwater Tour does not award the players a time bonus in the Armageddon once they reach move 60. If flagging is in play, then one should take the extra time. The game was decided on the board, however. Black was close to equalizing, but Artemiev always kept at least a little initiative, just enough to keep causing Black fresh problems. Starting to run short of time, Firouzja tried to open the game for complications, but his 23...e5 was a blunder: after 24.fxe5 Qe6(?) 25.g4 White won a piece for nothing, and Firouzja resigned a few moves later, after his last tactical tricks were thwarted.
And so it is a Carlsen-Artemiev final we have to look forward to. Carlsen is the favorite, obviously, but Artemiev seems to match up well enough to at least have a non-trivial chance. Let's hope so--it's always better to watch a contest that has some drama.