Chelsea 2-0 Leicester City

Costa's strike calmed Chelsea nerves at Stamford Bridge

• Summer signing Diego Costa scores on his home debut

• Eden Hazard scores after Cesc Fabregas assist

• Chelsea remain top of table after second win

Diego Costa was again on target for his new club as Chelsea eventually overcame a stubborn Leicester to maintain their 100% start to the Premier League.

The first half belonged to Championship winners Leicester, who caused the Chelsea defence some anxious moments.

In the second half David Nugent wasted a great chance when clear on goal.

But Chelsea attacked with more purpose after the break, with Costa scoring from close range and Eden Hazard drilling low beyond Kasper Schmeichel.

Leicester were the latest Premier League newcomers to fail in their attempts to thwart Chelsea, even though the hosts were a less vibrant and fearsome outfit than the one which impressed in victory over Burnley on Monday.

After a subdued performance in the first half, there were fears that the Londoners were reverting to the habits which proved costly in their pursuit of the title last season - slipping up against teams regarded as lesser opponents.

But the Blues did not have a striker as clinical as Spain international Costa, 25, during their last campaign, and the £32m summer signing's second league goal of the season was the nerve-easer that Chelsea desperately needed after only excellent goalkeeping from Thibaut Courtois had kept the score goalless.

Courtois was again preferred to Petr Cech, forcing the 32-year-old to readjust to the unfamiliar role of substitute after nearly 500 appearances as Chelsea's first-choice goalkeeper. From the bench, the demoted Cech could have watched his 22-year-old replacement make two fine saves, one in either half.

First the Belgium international prevented the light-footed Riyad Mahrez from scoring and, after the break, quickly came off his line to thwart Nugent, the former England striker who claims he has "unfinished business" in the Premier League.

The 29-year-old - a £6m purchase for Harry Redknapp's Portsmouth back in 2007 - has not scored in the Premier League since March 2010 and his wait must continue because of Courtois's reflexes.

The Foxes had the best away record in the Championship last season and twice came from behind at home to draw against Everton on the opening day, but ultimately lacked the guile needed to beat a Chelsea back four which was the most frugal in the league last season.

After their sluggish first period the Blues added urgency to their play in the second half and it needed an acrobatic save from Schmeichel to stop a Branislav Ivanovic header from reaching the top corner.

Following wave after wave of Chelsea attack - Oscar hitting the base of the post with a curling effort - a goal for the hosts seemed inevitable.

Again, Ivanovic was at the heart of it, charging down the right before his ricocheted cross found his striker inside the box. Costa controlled the ball with his chest and swept home from 10 yards.

Chelsea's second was preventable as Schmeichel allowed Belgium attacker Hazard's low effort from the left to slip underneath him.

Roman Abramovich could not contain his delight on the 11th anniversary of his first home game as Chelsea owner, which was against the same opponents.

The beaming Russian took part in a standing ovation when Costa made way for Didier Drogba, the 36-year-old striker making his first appearance at Stamford Bridge since rejoining the club in the summer as the match ended joyously for the Blues.

Leicester manager Nigel Pearson: "We're disappointed. Key moments didn't quite go our way. I thought we played exceptionally well in the first half but it's about taking your chances when you get them.

"There are more positives than there are negatives. We're not talking about us coming to places like this and being happy to lose the game, but I think the players showed what they're capable of. What we need to do is sustain it for the entirety of the game."

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Thibaut Courtois justified his selection in goal with two great saves to stop Leicester from taking the lead

Diego Costa has scored two goals from just two shots on target in the league so far

Hazard created six goal-scoring chances against Leicester before finding the net himself

Didier Drogba makes his first appearance at Stamford Bridge since re-signing for the club in the summer