PORTO, Portugal (REUTERS) - Jose Mourinho suffered a nightmare homecoming as Porto, the club he led to the Champions League title in 2004, inflicted a 2-1 defeat on his woefully out-of-sorts Chelsea side in Group G on Tuesday.
Manager Mourinho sprang a surprise before the game by leaving out Eden Hazard, Nemanja Matic and Oscar and the Londoners went behind after 39 minutes when Yacine Brahimi produced a surging run down the left and Andre Andre scored.
Brazil playmaker Willian equalised with the last move of the first half, curling a delightful free kick into the top corner of the net from 25 metres.
Porto then went back in front seven minutes after the break when Maicon stooped low at the near post to head a left-wing corner past keeper Asmir Begovic.
Diego Costa was agonisingly close to a second goal for Chelsea when his wicked drive from 25 metres hit the underside of the bar and came out.
But Chelsea, who won the Premier League last season but are struggling in 14th place in their domestic championship this term, could have fallen further behind at the Estadio do Dragao.
Porto laid siege to the visitors' goal in the last 20 minutes and Begovic had to be at his best to keep his team in the game.
Chelsea were denied a late penalty when Diego Costa flicked the ball around Ivan Marcano in the box and the defender deflected it away with his arm.
Overall, though, Porto were deserving winners as they joined Dynamo Kiev at the top of the group with four points from two games. Chelsea are on three while Maccabi Tel Aviv have yet to get off the mark.
Mourinho blamed his team's fifth defeat of the season on two bad moments. "We watched dozens and dozens of repetitions of Porto taking corners," he explained. "We were completely ready for that and in a moment when the game is under control we concede a goal that is ridiculous.
"They hit the post from a similar mistake. Apart from that the game was balanced. Two ridiculous moments and we were punished."
Victory was especially sweet for Porto goalkeeper Iker Casillas as the former Real Madrid stalwart broke fellow Spaniard Xavi's all-time Champions League record by featuring in his 152nd game in the competition.
"That was our best performance of the season," said Porto coach Julen Lopetegui. "I have to congratulate my team, these three points are totally deserved. "The players attitude was amazing, spectacular. It was tough and unfair to go to the dressing room at halftime with a draw but we reacted well."