Chelsea manager Luiz Felipe Scolari insists one more win will be enough for his side to reach the knockout stages of the Champions League despite a 3-1 defeat by Roma during a mistake-ridden performance at the Stadio Olimpico.
Poor defending and the "crazy" sending off of midfield playmaker Deco contributed to Chelsea's downfall as their struggling Serie A opponents stunned the Blues with three goals inside 58 minutes - from Christian Panucci and a brace from Mirko Vucinic.
Captain John Terry pulled one back for Chelsea in the 75th minute but any hopes of a comeback were dashed moments later when Deco was shown his second yellow card of the game by referee Luis Medina Cantalejo for taking a quick freekick.
Dismissed Deco could not believe the decision and said: "I'd already started to kick the ball when the referee told me to wait. I was already touching the ball, so there was nothing I could do. It was just crazy. What could I do?"
The midfielder will now miss their trip to Bordeaux and while the defeat left Group A wide open, Scolari believes Chelsea will qualify with one more victory.
"The group is open for all the teams now," Scolari said. "We have seven points but if we win one more game we are there.
"We need three points but the others maybe need to win two games. It is impossible for Roma and Bordeaux to do that because they have to play each other."
Scolari knew his side had been undone by their own mistakes, particularly two costly errors from Mikel John Obi. It was the first time he had seen his side concede three goals since taking over last summer and it was also one of Chelsea's worst European nights since their 5-1 crushing by Barcelona in 2000.
Mikel's bad pass to Deco forced the midfielder to foul Francesco Totti. The free-kick led to Panucci scoring the first goal and Mikel was at fault for the third when he gave the ball away to scorer Vucinic.
"We did not play very well and made mistakes at critical times," said Scolari. "We gave Roma two of their goals.
"Nobody followed Panucci into the area and Mikel made a mistake for their third goal. Roma have very good players and when you make mistakes like we did today, then they will kill you. When Roma score first it is difficult.
"But when you concede three goals like we did, you need to think about the next game. We need to work more and train more and maybe in the next game we will not make these mistakes.
"We had a few shots on goal in the first 30 minutes but their goalkeeper made some good saves. We tried to come back in the second half with Didier Drogba, Nicolas Anelka and Salomon Kalou but they closed us down very well.
"We cannot give clubs the space we did or make such mistakes. But I am not going to change my thinking just because of one game."
Although Deco will now miss the trip to Bordeaux later this month, Scolari is hoping that Michael Ballack will be fit enough to take his place.
"Maybe I will have players back like Ballack for that game," said Scolari. "So I will still have quality in my midfield."