Carlo Ancelotti fears Chelsea have no chance of overcoming Manchester United unless they make a vast improvement on Saturday's win over Wigan.
The Blues toiled to a 1-0 victory at Stamford Bridge thanks to an equally-unattractive goal from Florent Malouda.
Chelsea must make history to overturn Wednesday night's 1-0 Champions League Champions League defeat to United, who have never lost a European tie having won the first leg away from home.
And on only two previous occasions has a club won a Champions League tie after being defeated in the first leg at home.
"We have to play better but this is normal," said Chelsea boss Ancelotti, who admitted his side today had one eye on Tuesday's game.
"To win there, we have to play at our 100%."
Ancelotti's men do have hope, having won 2-1 at United last season in what proved to be a Premier League title decider.
However, they were easily beating teams at that point of the campaign, something that can hardly be said about their current run of form.
"Obviously, we have more difficulty compared to last season to score a lot of goals," added Ancelotti, who on Friday had denied he needed to win the Champions League to keep his job.
"We are not able to convert the chances that we create."
Fernando Torres was as guilty as anyone here after missing a golden opportunity to end his now-infamous 12-hour goal drought.
The Spaniard came off the bench for the final half-hour and had several opportunities, with the ball even put on a plate for him by Yossi Benayoun.
"Every one of us wanted him to score today," Ancelotti said.
"Sometimes, he was really unlucky.
"But I think we have to continue to have confidence in him.
"Maybe he will score the most important goals of our season."
Torres starting on the bench appeared to indicate he would be in the XI at Old Trafford but Ancelotti insisted he had yet to decide upon his strike force.
He did confirm he had settled on a system but refused to reveal what it would be, having abandoned 4-4-2 in favour of a 4-3-3 formation this afternoon.
It had little effect as the home side struggled to break down a Wigan team they had scored 14 goals against in their previous two meetings.
Malouda's winner was also not without controversy, with Torres arguably impeding Latics goalkeeper Ali Al Habsi before the Frenchman struck.
Frustrated Wigan boss Roberto Martinez said: "It's as clear as day that he's got his elbow in his face.
"I rate (referee) Howard (Webb) so much that I'm extremely disappointed.
"That was the call of the game."
Ancelotti refused to be drawn on the incident, having been denied what appeared a clear penalty against United on Wednesday.
He said: "I don't like to speak about this because of what happened last Wednesday. It's better to stay calm.
"Maybe it was a foul but I'm not sure."
Martinez, meanwhile, played down Hugo Rodallega's reaction to being substituted, with the striker storming down the tunnel.
"I'm pleased about that," Martinez insisted.
"Hugo should want to stay on because we're fighting for our lives.
"He's been respectful to his team-mates."
Defeat left Wigan rooted to the foot of the table but Martinez was adamant they would stay up if they repeated today's performance for the rest of the season.
"Our challenge is to carry on performing at that level for the next six games," he said.
"We've got 18 points to compete for and I'm just 100% sure that if we play in that manner, we'll get enough points to stay in the Premier League.
"I feel that we would've been top 10 if the season had started eight games ago."
Martinez spent the build-up to today's game defending fellow Spaniard Torres but asked whether he now had any sympathy for the striker, he said: "After what he did to my goalkeeper, not at all."
