The Arsenal supporters who filled the Emirates Stadium to watch the club’s reserves play a Carling Cup tie against Newcastle United this season are used to seeing Arsène Wenger’s youngsters record impressive victories, but the large number of empty seats last night suggested that they had little confidence that a win in their team’s final Champions League group match would have any significance. They were proved right, despite an Arsenal display that was more dominant than the score suggests.

To finish as winners of group H, Arsenal needed to beat Steaua Bucharest and hope that Seville failed to win away to Slavia Prague, but the Spanish team won 3-0. As runners-up, Arsenal could be drawn against one of the giants of European football in the round of 16, with FC Porto the least threatening among a group of potential opponents that includes Barcelona, Real Madrid and the two Milan clubs.

“It promises us a very interesting game in the last 16,” Wenger said. “I think it’s a good opportunity for us. Two years ago we played Juventus and we won. Last year we played PSV Eindhoven and we lost. I’m confident that we can beat anybody because I have a great belief in my players. The next match is in February and we’ll be even stronger than now.”

The result in the Czech Republic vindicated Wenger’s decision not to risk his strongest line-up before Sunday’s Barclays Premier League match against Chelsea. William Gallas, the captain, and Bacary Sagna, the right back, were the only members of the recent first-choice team to start, but Robin van Persie returned after two months out with a knee injury and did more than enough in 65 minutes to suggest that he will be involved against Chelsea.

“He looked sharp,” Wenger said. “His eye was there, his pass was there, he needs to regain a bit of confidence, but on the footballing side he looks like he’d never been out. He’s ready for Chelsea and we have some others who are injured, like [Cesc] Fàbregas, like [Alexander] Hleb, like [Mathieu] Flamini. I will certainly have to take a gamble on one or two. Three or four? That will be risky. Flamini maybe.” Fàbregas? “At the moment, no.”

Wenger watched last night’s match from the directors’ box as a result of the first touchline ban of his career, imposed after he was sent from the dugout in the defeat by Seville in Spain last month, and got a good view of Arsenal’s early pressure. Abou Diaby put the home team ahead after seven minutes, celebrating his return to the squad after a back injury by getting in front of Ionut Rada, the Steaua central defender, to collect a cross to the near post by Sagna and fire past Robinson Zapata, the Steaua goalkeeper.

Given the freedom of the flanks, and with Diaby and Van Persie doing more or less as they pleased, Arsenal could have scored many more, with Theo Walcott guilty of several misses. Four minutes before the interval, Nicklas Bendtner showed him how it was done, taking Van Persie’s pass, riding a tackle and slotting the ball low past Zapata.

Steaua, who took only one point from their six group matches, made little impression — although Mihai Nesu, the left back, left the imprint of his studs on Walcott’s legs on a number of occasions — until the 68th minute, when Dorel Zaharia, a substitute, looped a header over Jens Lehmann, who was given his first start since August 19.

“I don’t think he could do a lot with the goal,” Wenger said. “We had a good first half, but we were not clinical enough to finish what we created. Our game dropped in the second half and the main reason I could see — from upstairs — was physical because some of our players do not play a lot at such a demanding level.”

Uefa is to decide today whether to extend the touchline ban into the next round, but Wenger expects to be back in the dugout. “In the last 16 I would like to be down there, even though you see much better in the stand,” he said.

Arsenal (4-4-2): J Lehmann – B Sagna (sub: L Diarra, 71min), P Senderos, W Gallas, A Traoré – T Walcott, Denilson, A Song, A Diaby (sub: E Eboué, 71) – R van Persie (sub: Eduardo da Silva, 65), N Bendtner.Substitutes not used:L Fabianski, K Touré, Gilberto Silva, E Adebayor. Booked: Bendtner.

Steaua Bucharest (4-4-1-1): R Zapata – I Emeghara, D Goian, I Rada, M Nesu – A Neaga (sub: D Zaharia, 65), O Petre, F Lovin, V Cristocea (sub: R Surdu, 56) – N Dica – V Badea (sub: P Golanski, 80).Substitutes not used:C Cernea, E Bicfalvi, E Baciu, P Marin. Booked: Neaga.

Referee: Y Baskakov (Russia).