Diego Costa scored on his Chelsea debut as the title favourites came from behind to outclass newly-promoted Burnley at Turf Moor.There was the threat of an upset as Burnley’s Scott Arfield opened the scoring with a stunner from distance.But Burnley’s lead was short-lived as Costa levelled with a simple tap-in.Andre Schurrle scored Chelsea’s second after a cute Cesc Fabregas pass and Branislav Ivanovic struck from a corner to put his team in command.While Chelsea were unable to add to their goal tally in the second half – although the returning Didier Drogba did go close with a volley when he came on as a late substitute – it was a performance which fully justified why many expect Jose Mourinho’s men to be Premier League champions in May.The club’s problem last season was in front of goal, with the Londoners scoring 30 fewer goals than Manchester City and Liverpool, the two teams who finished above them in the league. In acquiring Costa for £32m from Atletico Madrid over the summer,the club appears to have addressed last season’s failings. The Spain striker was a dynamic and powerful presence up front and, importantly, more clinical than those who led the line during the last season’s third-place finish.The only blemish on Costa’s opening display was a yellow card for diving when through on goal after a defensive lapse by Ben Mee.But it was a harsh decision by referee Michael Oliver as replays showed the sprawled Tom Heaton had made contact with the striker’s protruding leg and, perhaps, the Spaniard should instead have been awarded a penalty.With the club’s other debutant Fabregas adding creativity to the midfield, Mourinho’s new acquisitions have helped make Chelsea a more potent side.It was Fabregas’s breathtaking first-time pass which set up Schurrle at the far post for a magical 25-pass team goal. And the former Barcelona midfielder was again the provider for his team’s third, taking charge of the corner which led to the unchallenged Ivanovic driving home from close range.Mourinho has also tinkered with his defence, which was the team’s strength last season – they had more clean sheets than any other team and conceded the fewest goals.The Portuguese said he was thinking of the club’s future when preferring 22-year-old Thibaut Courtois to Petr Cech, the club’s first-choice goalkeeper for the last decade.While there was a defensive lapse for Burnley’s goal, with the Belgian caught unaware when Arfield struck from the edge of the box to spark raucous celebrations, Courtois did produce a fine reflex fingertip save to deny Arfield another in the second half.It was not a result for the romantics, who would have hoped for a repeat of Burnley’s feats five years ago when they beat Manchester United under the Turf Moor floodlights in what was their home opener that season. But a team which cost £5m to assemble will, more often than not, struggle against such big-spending Premier League rivals.The financial gulf between the two clubs was neatly illustrated by the value of the two debutants on each side.While Costa and Fabregas were purchased at a combined cost of £59m, the players making their Burnley bows – Matt Taylor andLukas Jutkiewicz – arrived for a combined total of £1.5m.Defeat means Burnley’s wait for a first top-flight victory over Chelsea since August 1973 continues but last season’s Championship runners-up will take heart from this performance.They rattled an experienced defence with their opening goal and refused to cave in in the second half, although Chelsea’s intensity did dip after the break which could be the only slight on Mourinho’s men after an impressive opening victory.