There were two decisive games today and the third was a very lively draw. That's the way to enter the rest day!
Magnus Carlsen defeated Liviu-Dieter Nisipeanu with surprising ease. He stood a little better with White in a queenless QGA, but the advantage quickly turned decisive as Nisipeanu completely lost his way. With the win, Carlsen stayed half a point ahead of Sergey Karjakin to remain in clear first, and also kept ahead of Viswanathan Anand on the live rating lists.
Karjakin also won, catching an out-of-form Vassily Ivanchuk napping with the dirty trick 15...Bc8-e6 16.Rad1 Bxh3! Prior to White's 16th move the sac wouldn't have been as strong, as White's queen could subsequently retreat from c2 to d1, but once that avenue was cut off it was a different story. White still could have held with 17.d4, but after 17.c4? he wound up too far behind in material, and Karjakin won comfortably.
Teimour Radjabov and Hikaru Nakamura tested a Poisoned Pawn-like variation in the Najdorf whose name, if it exists, is unknown to me. (The line goes 6.Bg5 Nbd7 7.f4 e5 8.Nf5 Qb6 9.Qd2 Qxb2 and so on.) Both players were in prep for a long time, well past the official "novelty", and the result was a position where Nakamura was up an exchange but Radjabov's pieces were extremely active. This was still the case when they agreed to a draw, somewhat prematurely, on move 31. Radjabov may not have stood better, but he could have continued. With only 10 minutes left for his last nine moves, and having had to prove compensation for a while, he probably felt relieved even if the trend had been slightly in his favor the last few moves.
Standings After Round 5:
1. Carlsen 3.5
2. Karjakin 3
3. Nakamura 2.5
4-6. Radjabov, Nisipeanu, Ivanchuk 2
Pairings for Round 6 (on Friday):
Radjabov - Ivanchuk
Nakamura - Carlsen
Karjakin - Nisipeanu