Almost certainly out of the Premier League title race and on the verge of a Champions League exit, this competition represents the Gunners’ best chance of a trophy this season.
And Wenger accepts defeat to their long-time rivals at Old Trafford could spell disaster for Arsenal, with the Frenchman fearful it would have a knock-on effect on the fight for a top four finish.
“Monday night is a big game, and every big win in a big game has an impact subconsciously in the belief of the team,” said Wenger, whose side are just a point above United in the Premier League.
“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.”
Wenger added: “Once you get to the quarter-final you think that is (now) a good opportunity to win a trophy.”
Wenger accepts there had been times in the past when he “sacrificed” the FA Cup with hopes of further progress in Europe, the 4-0 fifth-round defeat at United in 2008 one particular painful example ahead of a crunch tie with AC Milan.
“The FA Cup was always badly positioned before the Champions League games, so you always had decisions to make,” said Wenger.
“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.”
Arsenal have a poor record at Old Trafford, where they have not won since September 2006 and suffered a heavy 8-2 defeat in August 2011.
Wenger, though, will pay no heed to that series of unfortunate events.
“When the team is not as good, they lose, it doesn’t matter what shirt they wear, or what stadium they play in – it is down to quality,” the Arsenal manager said.
“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.”
Story courtesy of: http://talksport.com