Jose Mourinho bemoaned the "ridiculous" error which contributed to Chelsea's 2-1 Champions League loss at his former club Porto.
The Blues lost to Porto on Mourinho's first return in 2004-05 and history repeated itself at Estadio do Dragao as Andre Andre and Maicon scored either side of Willian's free-kick.
The Blues are third in Group G after Dynamo Kiev beat Maccabi Tel Aviv 2-0.
Maicon's goal came from a corner, despite Chelsea being well prepared for such a circumstance.
Mourinho, who had criticised the attitude of his players on the eve of the game, said: "It was a good performance with two ridiculous mistakes.
"Sometimes you make that kind of mistake and you are not punished. We were punished.
"The second goal for us is a ridiculous mistake. We watch dozens of repetitions of Porto taking corners.
"We were completely ready for that and in a moment where the game is completely under control and we were preparing a change, to concede that goal is ridiculous."
The second mistake was from another set-piece, when a Danilo header hit a post, granting Chelsea a reprieve.
Mourinho reacted to the abject draw at Newcastle by dropping Eden Hazard and Nemanja Matic to the substitutes' bench, alongside captain John Terry, while leaving Loic Remy, Radamel Falcao and Oscar at home.
Mourinho refused to rebuke his players again, although Chelsea were easily exposed for Andre's opener.
Yacine Brahimi waltzed inside Branislav Ivanovic and behind Pedro, then fired in a shot which Asmir Begovic punched only as far as Andre, who hooked the ball in.
Instead Mourinho praised his players' reaction, with Ivanovic going close and Diego Costa hitting the bar and also appealing for a penalty for handball against Ivan Marcano.
"The basic thing in football to work is a defensive set play," Mourinho added.
"To concede the second goal was like (there was) ice in the players, but they react and they react in a positive way.
"Diego hit the post, Ivanovic had a chance with an open goal, one metre from the goal, the last minute situation, a clear penalty.
"I don't think my players deserve me to be critical of them, apart from the two mistakes that are difficult to accept.
"I'm not going to point the finger to one or to another. The two mistakes that cost us the game, a game that was fantastic."
Mourinho, who won the 2004 Champions League with Porto, was 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 insisted it was purely a selection decision not to bring Remy and Falcao to Portugal - and one he did not regret in hindsight - but 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 and Dynamo Kiev have four points, one ahead of Chelsea, who beat Maccabi Tel Aviv 4-0 in the first game and next travel to Ukraine.
Porto boss Julen Lopetegui was pleased with his side's performance.
"We are happy for the victory, but more about the mentality and the attitude," Lopetegui said.
"We conceded a goal at the end of the first half, in the second half we tried everything and managed to win the game.
"We had 10 chances in the first half, 10 in the second. We deserved to win."
Source: PA
