London: Chelsea striker Didier Drogba believes it would be a "disaster" if the club fails to qualify for next season's Champions League but insists he backs under-fire manager Andre Villas-Boas.

The 33-year-old Ivory Coast forward said Chelsea were currently battling through the most difficult period of the striker's career since signing from Marseille in 2004.

"If we don't make the top four it would be a disaster," Drogba was quoted as saying on Friday in several media reports.

"Every time we've started a season since I've been with Chelsea we never even finished as low as fourth.

"It is the hardest season I've known since I've been here."

Chelsea are currently just outside the top four following a disappointing 2-0 defeat to Everton last week which has raised questions about the position of the club's young manager Villas-Boas.

The Portuguese coach reportedly faced an open revolt from several senior Chelsea players earlier this week after a training ground bust-up.

However Drogba rallied to Villas-Boas' defence.

"It's hard for everyone at the moment, for the players and for the manager," Drogba said. "I think he's a big man and he's also learning. There's no age where you can say you don't learn any more.

"He came with his philosophy which is playing a bit more football than the other managers. That's how he succeeded in Porto so he wanted to do the same at Chelsea.

"You know how it is when you come with a lot of ambition and it doesn't go the way you want, it's difficult. It's not easy for him but he's not the only one who is responsible, we all are.

"In football everyone blames the manager first which is difficult for him because he is on the sidelines when we are playing but I guess that's football," said Drogba.