I would actually take Sanchez off if things don't change with like 20-15 minutes left. He is not playing good, either holds on the ball too long, or gives it away when he does release.
Because Coquelin was giving us an excellent base by breaking up their play and setting up ours. Now we have Cazorla and Ramsey in CM. Who is going to stop their counter's?
We've got just over 20 mins to score twice against the best defence in the competition. Not enough time.
At the time of sub we had just little under 30 mins left, for their players and fans that would have felt like a lot of time, with Coquelin we would have had more control, now this game is going to become end to end.