LONDON

Chelsea should be brim-ming with confidence after an unbeaten start to the season that has taken them to the top of the Premier League.

Instead, injuries to key players have unsettled the squad ahead of tomorrow's match against high-flying Aston Villa.

Chelsea were without Joe Cole, Deco, Ricardo Carvalho and Ashley Cole for Wednes-day's Champions League mee-ting with FCR Cluj and lost Didier Drogba to what could be a long-term knee injury during the match.

Defenders John Terry and Alex were also hurt during the match, suggesting that Chelsea will do well this weekend not to lose ground on co-leaders Liverpool, who are at Manchester City tomorrow.

"I need to think for the game on Sunday," said Luiz Felipe Scolari, who took his unbeaten streak as Chelsea coach to nine games with a 0-0 draw at Cluj. "I have a few days to build the team again. I don't know now what the possibilities I have for Sunday are."

But Scolari is getting used to coping without key players.

Midfielder Michael Ballack limped out of the season opener against Portsmouth and Chelsea still won 4-0, while Scolari then had to alter his plans for the entire campaign after Brazil striker Robinho opted to move to Manchester City rather than join his compatriot at Stamford Bridge.

Drogba is certainly out of tomorrow's match and Scolari is waiting to hear how long the Ivory Coast striker is set to be on the sidelines. Ligament damage is suspected, suggesting he could be out for weeks or even months.

That could lead to an extended run in the side for France forward Nicolas Anelka. The only other backups are Salomon Kalou and Franco Di Santo, who has never started a match for Chelsea.

"If Didier is out for a while, we will have to pitch in with goals from all around the team, which we can do, though the situation is not ideal," said midfielder Frank Lampard, who has five goals this season. "The experience is not really there, but I believe the quality is."

Ashley Cole should recover from a back problem in time to play, but Scolari is waiting on news of Terry and Alex.

The game is likely to provide a contrast in approaches, with a regularly changing Chelsea side coming up against a Villa team that has been unchanged for all six of its Premier League matches.

Villa manager Martin O'Neill's team hit third place after Saturday's 2-1 win over Sunderland.

"Premier League points are hard to come by," O'Neill said. "We seem to be getting into the habit of winning close games, which is very encouraging."

Unlike Chelsea, Liverpool have few problems ahead of its meeting with Manchester City. Tied with the Blues on 14 points - one more than Villa - Liverpool easily beat PSV Eindhoven in the Champions League in midweek to continue its own unbeaten start to the season.

"But we've won nothing," Liverpool captain Steven Gerrard said. "It's a good start but it's important to put silverware on table this year. We've gone two years without."

By tomorrow Chelsea and Liverpool will already know what their expected title rivals have done for the weekend. Defending champions Manchester United are at Blackburn today while Arsenal are at Sunderland.

Arsenal missed the chance to take sole possession of the Premier League lead last weekend when they slumped to a shock 2-1 home loss to newly promoted Hull, but rebounded with a resounding 4-0 Champions league win over FC Porto.

"Losing to Hull is not like a crime," striker Emmanuel Adebayor said. "It can happen in football. We had to show character and belief in our personality. But we took our lesson."

And that could be bad news for Sunderland, who haven't beaten Arsenal in the league since the opening day of the 2000-01 season. Black Cats striker Kenwyne Jones is recovering well from a serious knee injury he sustained in June, but still won't be back in time to face the Gunners.