Ivanchuk pushed hard today with the White pieces but Leko played solidly enough to draw to maintain his lead with just three rounds to go.
Aronian came back from his loss against Topalov to punish Vallejo. He is now only 1/2 point behind Leko. Aronian will face Leko in the last round.
Topalov had an uneventful draw against Radjabov with the Black pieces. He is still 1 point behind Leko. Topalov will face Leko in round 13.
Bacrot and Svidler engaged in a very exciting and dynamic game. It could have gone either way. At the end, the game ended in a repetition.
After round 11, the standings are:
1. 7.0 GM Peter Leko (Hungary 2740)
2. 6.5 GM Levon Aronian (Armenia 2752)
3-4. 6.0 GM Teimour Radjabov (Azerbaijan 2700), GM Veselin Topalov (Bulgaria 2801) 6.0
5. 5.5 GM Peter Svidler (Russia 2765)
6-7. 4.5 GM Etienne Bacrot (France 2717), GM Vassily Ivanchuk (Ukraine 2729)
8. 4.0 GM Francisco Vallejo Pons (Spain 2650) 
While Leko, Aronian, and Topolov are slugging it out with one another, it could prove interesting to see if Radjabov sneaks in. His last three rounds are against the tailenders. I don’t believe he’s had a better opportunity to win a major tournament against the big boys until now.