United produced an impressive performance in the San Siro to draw 0-0 with the Serie A leaders in the first leg of their last-16 clash on Tuesday night.
The holders created numerous chances to win the game, and Evra acknowledged a sense of frustration at failing to score an away goal.
However, the full-back believes United have the players capable of knocking Inter out in the second leg at Old Trafford in a fortnight's time.
"It's a little bit frustrating because we had a lot opportunities to score, particularly in the first half," said Evra.
"But overall we played very well.
"Now we are at home and we have to win, and I think we have the power to do that."
Evans praiseEvra also praised United's defence against Inter, with John O'Shea and Jonny Evans shrugging off injuries to start in the absence of Nemanja Vidic, Gary Neville, Rafael and Wes Brown.
The France international added: "We have had a lot of injury problems in defence recently, but we have still looked strong in every game.
"The Inter game is another example of that - we were without Vidic who is a very important defender for us, but Jonny Evans came in and played very well.
"I am really pleased for him because he's a top quality defender."