PORTO: Chelsea manager Jose Mourinho was left to defend his team selection and his side's performance after their slump continued on Tuesday with a 2-1 Champions League defeat to Porto.

Maicon got what proved to be the winning goal for Porto at the Estadio do Dragao after a superb Willian free-kick had cancelled out Andre Andre's opener in a tremendous Group G encounter as Mourinho returned to face his former club.

The Chelsea manager was furious with his team's display in drawing 2-2 with Newcastle United in the Premier League last weekend and made significant changes to his line-up, but on this occasion he simply said that two mistakes cost them dear in Portugal.

“It was a performance with two ridiculous mistakes. Sometimes you make that kind of mistake and you are not punished but we were,” said Mourinho of Chelsea's defending of the corner that produced Maicon's winner and of a later delivery that Danilo headed off the post.

“The second goal is a really bad mistake. We watch dozens of repetitions of Porto taking corners -- I thought we were completely ready for that.”

“We had another similar mistake when they hit the post but apart from that it was a balanced performance. The defenders played well, had no problems, but two ridiculous mistakes and we were punished.”

Mourinho, who coached Porto to Champions League glory in 2004, has now gone back to his old club three times with Chelsea and is still to win.

This defeat followed a loss by the same score in late 2004 and a 1-1 draw in 2007, but of more importance is the defeat in the context of Chelsea's season.

They languish in 15th place in the Premier League and have already suffered five defeats in 11 games in all competitions, winning only four times.

“The players reacted in a positive way,” added Mourinho of their second-half performance, when Diego Costa hit the woodwork and Chelsea had appeals for a penalty for handball against Ivan Marcano waved away.

“They tried to get a result. Diego hit the post, (Branislav) Ivanovic had a chance one metre from goal, there was a last-minute situation, a clear penalty.”

“So for me, I don't think my players deserve me to be critical at them. I'm not going to point the finger at one or another, but two mistakes cost us the game, a game that I think was fantastic.”

Selection worries

Mourinho had dropped Eden Hazard and Nemanja Matic to the bench, while Oscar, Loic Remy and Radamel Falcao -- the former Porto striker -- were not in the squad at all as Ramires, Willian and John Obi Mikel started.

He insisted that his team remained in a good position to qualify for the last 16, despite slipping to third in Group G behind Porto and Dynamo Kiev, who won 2-0 at Maccabi Tel-Aviv.

However, he admitted recent results were not helping when it comes to naming his starting line-up.

“When the team is not winning, it's normal that you have to make changes, but games like today are difficult to analyse after,” said Mourinho, who insisted the decision to drop Falcao and Remy completely was “no punishment”.

“Because the result doesn't mean we played bad. Big mistakes we made twice doesn't mean we defended bad. It's easy to make drastic decisions after a disaster, but this is harder.”

Chelsea now have crucial Premier League games at home to Southampton and Aston Villa before going to Kiev next month.

“It's obviously important for us to get two good results in the Premier League. The players need self-esteem and to feel good to be able to play.

“When everything goes against you it's difficult to get that feeling.”

Porto coach Julen Lopetegui was delighted with his side's display but refused to read too much into it before they face Maccabi Tel-Aviv in a double-header.

“This means three points. It doesn't mean anything more than that in terms of numbers,” said the Spaniard.

“It was a great game against fantastic opponents. I think they played well too. We had 20 shots on goal against a team like Chelsea, which is not easy.”