PARIS - Arsenal manager Arsene Wenger and Chelsea striker Fernando Torres enjoyed differing fortunes on the former's 64th birthday and the latter's 100th start for Chelsea in Champions League action on Tuesday. Arsenal went down to their first defeat since the opening day of the Premier League campaign, as last season's beaten finalists Borussia Dortmund beat them 2-1 at the Emirates Stadium.

Olivier Giroud cancelled out Henrikh Mkhitaryan's opener before Polish striker Robert Lewandowski scored the winner, although he was fortunate to be on the pitch having elbowed Laurent Koscielny earlier in the second half. After three rounds of games, Dortmund top the Group F table on goal difference from Arsenal, while Napoli also joined them on six points after disposing of Marseille 2-1 in France.

Wenger said he hadn't seen the elbowing incident clearly enough to comment but accepted that his side had not been at their best. "We have to look at ourselves for not being mature enough in situations like that. If you can't win the game you shouldn't lose it," he said. His Dortmund counterpart Jurgen Klopp, who watched from the stands as he serves a touchline ban, was delighted with the result and joked about ruining Wenger's birthday. "I am sorry about this, really. That is a problem of the date. I have a birthday in June when there are no matches. I'm always on holiday!"

Arsenal's English rivals Chelsea enjoyed better fortune against German opposition as a double from Torres -- taking his tally to 39 for the London club -- and one from Eden Hazard saw them to a 3-0 win and inflict a first defeat of the campaign on Schalke 04 in Group E. Both Chelsea and Schalke are on six points while Basel, surprise winners over Chelsea in their first match, are on four points after being held 1-1 by previously pointless Steaua Bucharest in Romania.

Steaua scored a late equaliser but have now gone a record 12 home matches without a win in the competition. Chelsea manager Jose Mourinho, who was returning to the ground where he won his first Champions League title with Porto in 2004, praised Torres. "He is not the kind of guy who hides behind the fee Chelsea paid for him," said Mourinho. "He always gives his best and he is a player I trust and respect."

The night's highest profile match ended in a 1-1 draw in Italy between AC Milan and Barcelona as Argentina's four-time world player of the year Lionel Messi showed he had put behind him the thigh injury that kept him out for three weeks with a fine equaliser. That goal cancelled out Robinho's opener but, despite dominating the second half, Barcelona were unable to break down an obdurate Milan defence and dropped their first points of the campaign.

They top Group H with a two-point advantage over Milan while Celtic kept their hopes alive of reaching the Last 16 for the second successive season with a 2-1 win at home to Ajax, which sees the Scottish champions move onto three points at the halfway stage. Barcelona coach Gerardo Martino was in prickly form, denying his defence was at fault for the Milan goal but frustrated they hadn't made it three wins from three. "It's a good point for us... but if you look over the 90 minutes I think we deserved to take more from the game," he said.

Atletico Madrid had no trouble in making it three wins from three as they rebounded from their first league defeat of the season at the weekend to trounce Austria Vienna 3-0 away in Group G. A double from Brazil-born striker Diego Costa -- one a magnificent solo run from the halfway line -- on his return from a European ban was the foundation of their victory. Atletico are now five points clear of Zenit St Petersburg, who won 1-0 at Porto in the night's other game, but coach Diego Simeone played down suggestions that they could be serious candidates to lift the European Cup for the first time come May. "We know the difficulties that come with playing in the Champions League, especially combining three competitions with our squad," he said.