The Gunners head to Old Trafford to contest the biggest tie of the sixth round, with both sides currently holding a top four position in the Premier League table.
Wenger, whose team are bidding for back-to-back successes in the competition, said: “It is a big game, and every big win in a big game has an impact subconsciously in the belief of the team.
“It (winning the FA Cup last season) gave us energy because we had a few years without winning a trophy and on that front it was vital.
“This team has a good mentality because we had a slow start this season and every time when we lose a big game, you see how much the players are touched.
“I think the mentality is very healthy, they want to do well and we will be focused on Monday night.”
As for the importance of progressing in the FA Cup, Wenger added: “Once you get to the quarter-final, you think this is a good opportunity to win a trophy.
“The FA Cup was always badly positioned before the Champions League games, so you always had decisions to make.
“A player who was a bit on the edge. What do you sacrifice? It was always the FA Cup in the end.
“Sometimes as well I did not sacrifice the FA Cup years before and we paid the price because we lost one or two important players two or three days before an important game.”
And Wenger is unconcerned that Arsenal have not won at Old Trafford since September 2006: “If I have learnt something in my life, it is that the performance on the day decides the outcome of the day, not where you play.”