
Magnus Carlsen didn't manage to win in his first party with white in Corus Chess 2007. According to my computer, he was positionally ahead for most of the game, but unable to turn the advantage into a point - instead, he lost. After 27 moves, this was the situation:

Here, 28. Be5+ seems obvious to me, but Magnus chose
28. h3 instead. (According to comments on this post, Fritz also prefers 28. h3, so I guess that move's advantages positionally outweights the advantages of 28. Be5+)
A few moves later, Magnus again had a chance to nudge the game in the right direction, when Navara gave Magnus this situation:

He played
32. a5, but my computer suggests 32. c6, which would seem to force an exchange of queens, and giving the black rook a whole lot of trouble as well. What happened in the game was that the pawns were exchanged before the queens, giving the black rook an easy game.
(Chess is so easy as long as I can rely on my computer instead of playing myself...)
I hope Magnus does better tomorrow - he will need a bit of confidence in the run-up to the matches against Anand (Tuesday), Aronian (Thursday), Kramnik (Sunday) and Topalov (next Wednesday).