Chelsea stars believe the return of Didier Drogba has given them a vital boost as skipper John Terry demands an end to the inconsistent form that has threatened to derail their season.

Drogba came off the bench against Cluj last night to score a 71st-minute winner. The 2-1 victory at Stamford Bridge secured Chelsea's place in the knock-out stages of the Champions League but it was another far-from-convincing performance from a team that still look nervy in big games.

Terry believes Chelsea have no chance of winning the coveted European crown if they continue to play like they did last night, although he agrees that Drogba's return to the side, after completing a three-match suspension for throwing a coin at Burnley fans during the Carling Cup tie last month, gives them an edge they have been missing.

With Roma's 2-0 win over Bordeaux ensuring they secured top spot in Group A, second-placed Chelsea now risk facing Barcelona or one of Juventus and Real Madrid in the next round.

Terry said: "Is there room for improvement? Massively. If we want to go all the way to the final as we did last year, we really have to up our game.

"We are in the knock-out stages now, so we have to make sure we are on the ball and improve our game. Things haven't been clicking but let's not get panicky.

"We are still second in the Premier League and we have qualified for the last 16 of the Champions League. We still have a lot more to give in this competition and the Premier League.

"We didn't play too well. The key was not to panic and thankfully we got the goal when Didier came on. It is a great boost to have him back.

"He gives us a new dimension when he's in the team and he's now ready for a long run in the side. He has been frustrated with being suspended but he is back now."

Salomon Kalou, who scored the opening goal, is delighted to see the 30-year-old back in action. He said: "Didier is a vital player for us, so it is important we keep him fit."

Deco also acknowledged the importance of having Drogba back in the team. The Ivorian is believed to have held talks with Inter Milan last month but Deco said: "We need Didier. He is a great player and now he has to be strong and play with confidence."