London - Arsenal manager Arsene Wenger vowed his team had nothing to fear after they advanced to the knockout phase of the Champions League and a likely showdown with one of European football's heavyweights.A below-par Arsenal were made to work hard for a 3-1 victory over Partizan Belgrade on Wednesday, with Theo Walcott and Samir Nasri scoring the decisive goals after the Serbs' striker Cleo had cancelled out Robin Van Persie's opener.However the result was not good enough to clinch first place in Group H, meaning that the Gunners now face a last 16 tie against either Barcelona, Real Madrid, Bayern Munich or Schalke 04.Wenger acknowledged that the possibility of a match against Barcelona - who destroyed Arsenal 4-1 in the Nou Camp last season - was a daunting prospect.However the Frenchman insisted his team would be confident of progressing regardless of who they were eventually drawn against."You would have to say let's be realistic. Barcelona is the super-favourite in this competition at the moment," Wenger said."But we take what we get and if it's Barcelona, it's Barcelona. We've played them already last year and we'll see."Last year we went out against them. But I feel we had some room to do better because it was 2-2 at home and we were leading 1-0 over there."We lost 4-1 but it depends whether we have our best players available, a good level of confidence."Wenger also believes that his team - which is currently leading the Premier League and has advanced to the semi-finals of the League Cup -- may also improve by the time the Champions League resumes in February."We are in a strong position in the league, we are qualified in the Champions League, we are in the semi-finals of the League Cup," he said."So overall there are plenty of exciting challenges in front of us. But we have room for improvement and I believe we will."Wenger knows an improvement on his team's performance against Partizan will be necessity if they are to progress in the Champions League.While the Londoners always looked to have plenty in reserve, perhaps with one eye on next Monday's Premier League showdown with Manchester United, Wenger was unhappy with an uncharacteristically stilted attacking performance."I was not completely happy with our offensive game tonight but maybe it was down to the quality of Partizan's defending because they defended in an intelligent way and very well," Wenger said."We have played some great games since the start of the season and tonight was certainly not our best. But what is important is that we are in the competitions."We didn't find our pace in the game. We didn't manage to find openings in their defence and they defended very well. Our passing lacked a little bit of incisiveness," Wenger added.Arsenal's captain-for-the-night Van Persie said the Gunners believe they can finally end their five-year trophy drought this season."Everything starts with belief," Van Persie told Sky Sports."If you don't believe you'd better stop playing football. We do believe we can achieve things this year."Van Persie said he was not fazed by the fact that Arsenal's second place finish could mean a trip to Barcelona or Madrid."As a fan of football I'd love to be involved in a game against either Barcelona or Madrid but we'll just have to see what happens in the draw," he said.