Baku World Cup Round 5.1 and 5.2

CM vinniethepooh
Sep 24, 2015, 8:32 PM |

This is the results of round 5.1 and 5.2 in Baku World Cup:

Eljanov won against Nakamura in the first round,then he drew.That takes him to the semis.Giri comfortably drew in first round,then he outplayed MVL in a rook endgame and even he is through to the semis.Mamedyarov kept pressing in the first game when he had two pieces for a rook.But he didn't convert.He made Karjakin suffer,but it was a draw.The next game was a quick draw.They will decide everything on the tiebreaks.Svidler and Wei Yi played a quick draw in the first game.In the next game Svidler had an edge but it petered out to equality.

Here is the endgame with full analysis:
Can you find Eljanov's idea from which he gained a nice advantage?
Here is the analysis,I am only analysing the moves of the puzzle because they are most important.