Tipped off by Facebook

Vassily Ivanchuk has won yet another event, this time the Magistral Rapid tournament. He defeated Vishy Anand in the 4 game final 2.5-1.5, after Anand blundered and lost the final game in 16 moves.
However I found out about it in a rather circuitous way, after seeing a comment by GM Stuart Conquest on Facebook, of all places. It turns out that the Ivanchuk-Anand game was anticipated by the game Conquest-Zaichik, 1988 with both games taking the same course up until move 15. On move 15 Ivanchuk found a stronger move than Conquest (as Stuart himself pointed out on Facebook), so strong in fact that Anand only played one more move before resigning.

Ivanchuk,V (2740) - Anand,V (2803) [E55]
XXI Magistral Rapid Final Leon ESP (4), 01.06.2008

1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.e3 0-0 5.Bd3 d5 6.Nf3 c5 7.0-0 dxc4 8.Bxc4 Nbd7 9.Qe2 cxd4 10.exd4 b6 11.d5 Nc5 12.Rd1 Qe8 13.Nb5 exd5 14.Nc7 Qe4 (D)
15.Rd4N Here is the improvement found by Ivanchuk. [ RR 15.Nxd5 Qxe2 16.Nxf6+ gxf6 17.Bxe2 Ba6 18.Bxa6 Nxa6 19.Bh6 Rfd8 20.Nd4 Bf8 21.Bxf8 Kxf8 22.Nf5 Nc5 23.g3 Na4 24.b3 Nc3 25.Rxd8+ Rxd8 26.Kg2 b5 27.a3 Rd3 28.Re1 Nd5 29.a4 Nc3 Conquest,S-Zaichik,G/Tbilisi 1988/TD/½-½ (42)] 15...Qg6 16.Nh4 1-0