World Cup Recap: Day 14 (Quarterfinals, second classical game)

And then there were six.

Hikaru Nakamura could manage no more than a draw today, when he needed a win to stay alive. Consequently the #2 seed heads home, and Pavel Eljanov heads into the semifinals. Meanwhile Anish Giri overcame his drawish reputation and scored his own victory, the only decisive game of the day, sending Maxime Vachier-Lagrave packing. Giri is now the only top-ten seed left in the competition, and has taken over as the favorite to win it all.

Two other matches were drawn, as they were yesterday, and will be settled tomorrow with tie breaks. That means Peter Svidler and Wei Yi will battle for the right to face Giri, while Shakhriyar Mamedyarov and Sergay Karjakin will face off to see who must contend with Eljanov. The two players who got the results they needed today to avoid tie breaks are of course the biggest winners of the day, while the two eliminated players saw the biggest drops in their odds of reaching the finals:

Seed Player Rating New Odds of Reaching Finals Change
4  Anish Giri (NED) 2795.7 69.9% 27.1%
26  Pavel Eljanov (UKR) 2751.4 48.1% 13.6%
19  Shakhriyar Mamedyarov (AZE) 2745.0 21.0% 4.5%
16  Peter Svidler (RUS) 2733.6 14.6% 0.1%
11  Sergey Karjakin (RUS) 2764.6 30.9% 0.0%
24  Wei Yi (CHN) 2737.0 15.5% -3.9%
2  Hikaru Nakamura (USA) 2806.0 0.0% -18.1%
21  Maxime Vachier-Lagrave (FRA) 2764.4 0.0% -23.3%

Note that Giri is one of two players who entered today playing somewhat by proxy for others who had already been eliminate. He is nearly guaranteed a spot in the Candidates Tournament regardless of his remaining results, thanks to his strong rating over the course of the year, but this win brings us up to nearly a 70% chance now that he will earn his berth via the World Cup, opening a ratings vacancy for either Kramnik or Grischuk. If Giri does end up in the finals, then every classical game played by those two later this year (particularly at the European Club Cup) will be of the utmost importance as they are separated by the slimmest of margins in the rating calculations. The other proxy player was Nakamura, who could have carried Jakovenko into the Candidates Tournament by reaching the finals here. Unfortunately for Dmitry and his fans, the Russian’s chances fell to zero with Hikaru’s elimination.

The grueling schedule continues tomorrow with the 15th straight day of action, as two crucial tie break matches are played. Afterward an actual scheduled rest day finally shows up in the tournament calendar, so those players who advanced today actually get to enjoy two days off to recuperate, and to prepare for the next round.

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5 thoughts on “World Cup Recap: Day 14 (Quarterfinals, second classical game)

  1. Why did Wei Yi’s odds drop by 3.9%? It can’t be due to Giri’s win over MVL, since (1) Giri’s live rating isn’t that much higher than MVL’s, and (2) Svidler’s odds didn’t drop nearly as much. I have trouble believing that drawing with the White pieces would reduce his chances by that much either. So what’s going on?

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    • It is precisely those two factors. Relatively small things have surprisingly large impacts with so few contenders left.

      The 32 point rating gap between Giri and MVL means that Wei Yi only advances 30.5% of the time against Giri, but 40.3% against MVL. Yesterday there was a 37.6% chance of the easier matchup, today the harder matchup is guaranteed. That right there drops Wei’s chances in a hypothetical semifinal match, taking a weighted average, from 34.2% down to 30.5%.

      Meanwhile, only drawing with white today means he goes to tie breaks where he’s a modest 50.9% favorite to advance over Svidler, whereas yesterday with one game as white left to play he was a 56.7% favorite.

      Put it together and yesterday he had a 56.7% chance of reaching the semis and having a 34.2% chance there, for a 19.5% chance at reaching the finals.

      Now after Giri won and he just drew with white, that drops to a 50.9% chance of being a 30.5% underdog, which multiplies to a 15.5% chance.

      There’s some rounding involved, so when you carry the hidden decimal points 19.5 minus 15.5 ends up equaling 3.9 percentage points, which is how much worse Wei’s chances of reaching the finals are today than yesterday. A butterfly flaps its wings, you know?

      Ultimately he lost about two percentage points from each of the two factors, which is why you don’t see the same impact to Svidler. Svidler was equally hurt by Giri’s win, but where Wei drawing with white hurt him, it benefited Svidler equally, so Svidler saw basically no net change in his chances, 2-2=0.

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    • Well, technically I suppose it’s still possible for Karjakin to lose to Eljanov, Svidler to lose to Giri, and then Kramnik and Grischuk to BOTH lose 25+ rating points in a disastrous European Clup Cup, while Aronian wins every game he plays and gains 25 points of his own, and sneaks into the #2 ratings spot.

      That seems awfully unlikely. Call it a 99.995% chance of at least one Russian at the Candidates.

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