Jose Mourinho has criticised his Chelsea defence for making "ridiculous mistakes" during Tuesday's 2-1 Champions League defeat at Porto.
Mourinho led Porto to Champions League glory in 2004 before joining Chelsea for the first time but lost on his first return to the Estadio do Dragao that December.
The Portuguese coach fared no better this time round as Andre Andre and Maicon scored either side of Willian's free kick in the Group G clash to consign Chelsea to their fifth defeat of the season.
Mourinho blamed his players for a lack of concentration during the defeat, with BBC Sport reporting the coach as saying: "We watch dozens and dozens of repetitions of Porto taking corners. 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."
Diego Costa unsuccessfully appealed for a penalty late in the game following an apparent handball by Ivan Marcano, and Mourinho believes his side should have been awarded the spot kick.
"The most basic thing in football is a defensive set-play," he said. "We had chances after that to get a positive result and we had a clear penalty -- so for me I am not here to criticise the players.
"I am not going to point the finger but two mistakes cost us the game. The team played well against a difficult opponent. The Champions League brings a different atmosphere."
Mourinho was also scathing in his criticism following Saturday's draw at Newcastle, which sees the defending champions 14th in the Premier League with two wins from seven games. He is no closer to finding the answers to Chelsea's poor form.
Mourinho -- who has been urged to restore John Terry to the side by Rio Ferdinand -- insisted it was purely a selection decision not to bring Loic Remy and Radamel Falcao to Portugal.
He said he did not regret the decision in hindsight, but admitted he does not know his best starting XI at present.
"No punishment. Just a decision, option," Mourinho added. "When the team is not playing and winning matches on a regular basis, it's normal that you have to make changes.
"When you play a disaster it's easier to make drastic decisions. When you play like today and you don't get a result, it's more difficult.
"The result doesn't mean that you played bad. The big mistakes we made twice doesn't mean that the team defended badly."
Mourinho's scathing comments did not have the desired effect and he suggested he would change tact ahead of Saturday's match at home to Southampton.
"Good feelings, happiness, self-esteem -- players need that to play," he added. "When everything goes against, it's difficult to have that feeling. So let's try. Let's try next Saturday."
Porto coach Julen Lopetegui was delighted with his side's performance, saying: "The players' attitude was amazing, spectacular. It was our best performance of the season.
"I have to congratulate my team. This three points are totally deserved. It was tough and unfair to go to the dressing room at half-time with a draw, but we reacted well."