The Gunners take a 2-1 lead and Fabregas to Spain for Tuesday night’s second leg clash in the last 16 of the competition.
Fabregas says he will be fit to face his former club after his hamstring injury kept him of Saturday’s 0-0 draw with Sunderland.
England star Jack Wilshere is fit for Barca but Alex Song (knee) is out while Fabregas is rated at 90% to play.
“We need some fresh legs for the Nou Camp because we will have to run a lot,” Wenger said.
“We have not enough security to sit back and defend. You can’t go to Barcelona, play for a 0-0 and not try to score.
“It’s also not the personality of this team. We will try to score when we get the ball back.”
Wenger reckons the Barcelona clash was on his players’ minds as they failed to find the net in Saturday’s scoreless draw at home to Sunderland, a costly result in light of Manchester United’s defeat at Liverpool.
“Barcelona has been a little bit in the heads of the players, it is always subconscious,” said the Arsenal manager.
“However, I still feel that, especially in the second-half, we did enough to win the Sunderland game but it didn’t work.
“It was a match short on chances, so of course these type of decisions are frustrating, and also when you look at the impact it has on the season, because recently we have really been punished.
“However, now we have a big game on Tuesday and the size of the game will help. The team is mentally strong and the season is not over.”