Dimitrov G. vs Rublev A. prediction

Grigor Dimitrov sits under number 3 in the world rankings, but yesterday in second round of this competition he had big problems against world number 186 McDonald. Dimitrov clinched five sets win, but in the fourth set he failed 0-6 and struggle in the fifth set for the final 8-6. On the other side Rublev sits under number 32 in the ATP world rankings. He is promising youngster and already defeated two good players Ferrer and Baghdatis in previous two rounds. Head-to-head Rublev leads 1-0 after he defeated in straight sets Dimitrov at US Open only four months ago in third round. I think Dimitrov is not at his best days at the moment and he will have big problems again. My pick is Rublev to win.