The Blues head to Spain with a hard-earned 1-0 lead from the first leg at Stamford Bridge last week, where the holders produced a lacklustre display on a rainy night in west London.
Chelsea caretaker boss Roberto di Matteo made sweeping changes for Saturday's Barclays Premier League clash at Arsenal, where they battled to a goalless draw.
Barcelona, meanwhile, suffered another defeat when beaten by La Liga leaders Real Madrid, who inflicted a first home defeat on the Catalan giants in 54 games.
Wenger also masterminded victory over Barcelona in Europe last season, winning the first leg of their last 16 tie 2-1 at Emirates Stadium, before going out 4-3 on aggregate in the Nou Camp - where Nicklas Bendtner was within inches of netting a late away goal which would have sent Arsenal through.
And the Gunners boss sees no reason for Chelsea not to be in a positive frame of mind next week.
He said: "It is far from impossible to qualify there because Chelsea go even in a better position that us, they won 1-0 - it is a fantastic result 1-0.
"Also, the Barcelona we have seen the other night it is not the Barcelona of last year.
"As well, Chelsea could rest eight players against us. Barcelona could not afford to rest nobody on Saturday night."
Chelsea drew some criticism for perceived negative tactics in their victory.
While Wenger understands sometimes it is not always possible to be on the offensive, the Gunners boss feels Chelsea could effectively kill the tie by showing some ambition.
"You wonder as well is it not worth to try to score a goal? That would mentally be a massive blow to them because I have seen last year when we scored last season, yes it was a lucky goal, but I could see suddenly they became very nervous," he added.