Speaking to the official ManUtd.com podcast, Red Voices (available to download from manutd.com/podcast on Thursday), the central defender explained that the boss has already taken steps to eradicate any tiredness ahead of the weekend encounter with Reading.
"We had a couple of days off after the Chelsea game," revealed Evans on Wednesday. "The manager decided to give us an extra day or so's rest so we came in today and got the legs going again but it wasn't too hard out there on the training pitch.
"Obviously, I didn't play in the Real Madrid game so I wasn't feeling physical tiredness but, on Sunday, I did feel a bit tired and a bit drained in the second half. I think the mental side of it drains you. There were a lot of emotions during the week and we have to try to switch off from that and prepare for the next match.
"When you're at Manchester United, a lot of the time it's about preparing yourself mentally for every game. You know you have to be at the top of your performance and you can't let standards slip. I think what caught us out a bit against Chelsea at the weekend was we got off to a good start but the mentally-drained side really showed in the second half."
Evans is relieved to still be in the FA Cup after David De Gea pulled off a tremendous stop to thwart Juan Mata in the closing stages to prevent Chelsea from completing a remarkable comeback.
"Probably coming out of the game with a draw was the best result for us in the end," he added. "We've got a replay coming up so we're glad to