This is what Grischuk said about his endgame:
Grischuk praised his opponent’s play: “I think Teimour played very well. I completely underestimated the dangers in the endgame.” Radjabov, who probably missed a chance on move 56: “I don’t know if I’m winning but it should be close.” About defending the infamous f+h rook ending, Grischuk said: “I had quite some experience. In one month I had two games with Pavel Eljanov. Both times I had the pawns myself; I drew the first one and won the second. And I read some articles about it.”
Just take a look at the final position in the four games played yesterday. If you want more advanced lessons in the endgame, just start analysing from farther back in these games!