We had another round like we're used to at the World Cup, with lots of fight and lots of wins. There were also plenty of mistakes - chess mistakes and mental errors too, which is to be expected near the end of such a long tournament.
Vassily Ivanchuk was in the best shape of anyone after the first day of round 5, as he had defeated Teimour Radjabov while all the other games were drawn. No more. Radjabov devised an enterprising piece sacrifice in a quiet-looking Symmetrical English, and it worked like gangbusters. Soon Radjabov regained the material (and then some) while enjoying strong attacking chances as well. Ivanchuk was crushed, and so they're off to tiebreaks tomorrow.
Judit Polgar was also in good shape coming into the round, having drawn easily with Black on day one. She enjoyed a reasonably promising position in today's game after sacrificing a pawn to set up a strong position where her light-squared bishop was extremely strong while Svidler's dark-squared bishop was correspondingly passive. Maybe at one moment she could have enjoyed a small advantage (and likewise Svidler too may have missed some chances earlier), but most of the way equality was the most she could have hoped for, and that was certainly true on her 30th move. Polgar should have played 30.Qh5, inviting a repetition, but instead hoped for more. Unwarrantedly. Svidler was able to consolidate his extra pawn and take care of his king's problems, and when Polgar continued to play as if she was better, Svidler counterattacked, winning almost immediately.
Simply put, Polgar lost her objectivity, and it cost her the game. Oddly, assuming Mark Crowther has transcribed her comments at the post-game press conference correctly, Polgar began by lamenting that "my luck was not with me today". That seems somewhat ungracious, slightly absurd after the colossal servings of luck she received in the Dominguez match, and odd considering her easy draw with Black yesterday despite mistakenly preparing to have White. (I think her point was that because she had an extra day of White preparation, Svidler decided to play 1...c5 rather than 1...e5 in their game, and in that way she was "unlucky". Svidler offered a different explanation in the press conference, but since Polgar got a very good position in the middlegame in any case, it's again hard to see what this "luck" business is all about.) Even aside from all of that, I can't see any way in which she was unlucky in the last game. She just got greedy, overpressed and lost. There wasn't some long combination she had seen that didn't work because of some ingenious resource Svidler hadn't seen but found at the last second. She just pushed where there was nothing to be had, and her opponent was able to use his trumps to win.
Ruslan Ponomariov also won with Black to advance to the semis; he and Svidler will reprise their battle from the semi-finals of the 2002 FIDE World Championship. (Ponomariov won the title, and by implication their match as well.) He got there by grinding out a very long victory in a knight vs. bishop ending. There were a lot of errors, as is to be expected (tired opponents without a lot of time to think), but Ponomariov's win was the most logical result given the game's general trend.
Finally, David Navara should have also qualified for the semi-finals today. He had done a great job of outplaying Alexander Grischuk from an equal opening, but at the last second, by his own admission, he got careless. 49.Nc3 would have won a second pawn and rendered the win trivial; instead, his 49.Ke5 allowed Grischuk to escape.
Tomorrow, then, the Ivanchuk-Radjabov and Grischuk-Navara matches go to tiebreaks. No rest for the players, commentators or bloggers!