Successive away defeats by Shakhtar Donetsk and Braga had left the Gunners - who opened their European campaign with three straight victories - still needing a result from today's clash against Group H whipping boys Partizan Belgrade to secure safe passage through to the knockout stages for the 11th successive season.

After a lacklustre start, Robin van Persie fired the home side ahead from the penalty spot for his first goal of the season, only for Brazilian striker Cleo to net a shock equaliser on 52 minutes.

However, substitute Theo Walcott volleyed Arsenal back into the lead with man-of-the-moment Samir Nasri sweeping home a third before the hosts finished with 10 men when defender Bacary Sagna was shown a red card for a professional foul on 85 minutes.

Wenger's men were runners-up to Shakhtar and so will face Real Madrid, Barcelona, Bayern Munich or Schalke in the knockout stages.

"I was never really nervous - worried, yes, because in football you can never say that you don't worry when you are 1-1," reflected the Arsenal boss.

"It was bit of a low-key game because we didn't find out pace or openings in their defence.

"I felt our speed of passing was not incisive enough and it was a bit nervous as well.

"They were focused on closing us down everywhere.

"But I felt we had the resources to score and in the last 20 minutes they would drop a little bit physically."

Arsenal were dumped out in the quarter-finals by Barcelona last season, and could be set for a swift return to the Nou Camp when European competition resumes in February.

"Let's be realistic, Barcelona are the super favourite at the moment," Wenger said, "but we take what we get and if it is Barcelona, it is Barcelona.

"We have played them already last year and we will see.

"It depends whether you have your best players available, whether we have a good level of confidence then.

"It is very difficult to predict how far you can go.

"Now in the last 16 it becomes a different competition, a cup competition and that means for 180 minutes you have to be at your top."

Wenger challenged his team to maintain their domestic form, which sees table-toppers Arsenal at Barclays Premier League title rivals Manchester United on Monday night, and use that to boost their European hopes.

"Overall we are in a strong potion in the league, we are qualified in the Champions League, we are in the semi-final of the Carling and we start the FA Cup in January. There are plenty of exciting challenges in front of us, but there is room for improvement and I am confident we will," he said.

Wenger added: "Tonight was certainly not our best, but when we play now in the last 16 hopefully we have done well in the Premier League and the Carling Cup and we can have a high level of confidence because that will be needed."

One sour note for Arsenal was the injury to full-back Kieran Gibbs, which saw the England defender replaced after 23 minutes.

"Kieron Gibbs has a twisted ankle, an ankle sprain. I don't know how damaged his ankle is - he will have a scan tomorrow. He is unbelievably unlucky," Wenger said.

Partizan coach Aleksandar Stanojevic was pleased with his team's efforts despite finishing their Champions League campaign with no points.

"We had some good moments in all the matches, but made too many mistakes against quality opponents, which is why we finished bottom", he said.

"Arsenal were not that much better than us, they had just 57% of possession, but after our mistakes, they scored three goals and it was not easy to come back.

"However, I am satisfied with our season in the Champions League, it was a big experience for our young team."

As to who could go on to win the competition, Stanojevic said: "I would like to see a club who play in an attractive way, like Arsenal or Barcelona, to lift the Champions League."