THE iron mental strength which brought Chelsea such success under Jose Mourinho is conspicuous by its absence in Andre Villas-Boas's side, according to former Stamford Bridge midfielder Michael Ballack.
The 35-year-old proved central to Bayer Leverkusen's successful attempt to compound Chelsea's worst start to a campaign in a decade on Wednesday night, as the German side came from behind to beat their Premier League opposition 2-1 in the Champions League.
Villas-Boas's side must now win or secure a goalless draw in their final group game, against a resurgent Valencia at Stamford Bridge next month, to qualify for the knockout stages.
Given the parlous state of Chelsea's confidence, though, that task is by no means a foregone conclusion. Ballack, who warmly greeted Ashley Cole and Frank Lampard before engaging in a lengthy conversation with a scowling John Terry as he spoke to Europe's press at the BayArena on Wednesday, remains confident his old team-mates will qualify, but admits they look a shadow of their former selves.
"We knew before the game they were in a difficult moment," Ballack (pictured right) said.
"But it's only when you play against a team on the pitch that you see what is really happening.
"You get a clearer picture than when you just see a team on television. We could feel it on the pitch every minute,especially at the beginning of the match, that they were not as strong as they normally are.
"Even when they were 1-0 up, we could sense that they didn't have the strength mentally they normally have. We felt that on the pitch, and even though we were lucky to score in the last minute, we thought we had a chance of doing that.
"It is still in their hands, but it is not the best moment for them. It's difficult for me to say the reasons. I'm not in the dressing room so I'm not that close to what is going on at the moment. All I can say is what I see and maybe the results are not the best. With every defeat, you can see they are losing confidence."
At such times during Ballack's four years in England, it was to the club's most driven characters that the squad turned; now, he says, the likes of Terry and Lampard must prove they remain in possession of the indomitable spirit they once boasted.
"It is not just about the coach, it is about the players too," he added.
"They have to get out of this situation. I think there are enough big players, experienced players, still in the dressing room.
"They have to do it now. You can't just look at the young players and criticise them. This has to come from the older, experienced players, especially now."