Oscar and Cesc Fabregas scored sublime goals as Barclays Premier League leaders Chelsea overcame troublesome obstacles in winning a fiery derby with Crystal Palace 2-1 at Selhurst Park. Diego Costa, scorer of nine goals in his first seven league games, was missing after persistent hamstring trouble in the opening weeks of the season, but Chelsea coped with the £32million Spain striker’s absence. A brilliant early free-kick by Oscar, excellent throughout, took the pressure off Loic Remy, Costa’s deputy, who was making his first Premier League start for Chelsea. And Damien Delaney gave the visitors an escape when he received a second booking just three minutes after Cesar Azpilicueta had been sent off for a reckless two-footed lunge on Mile Jedinak. Fabregas struck six minutes into the second half after playing return passes with Eden Hazard and then Oscar to surge into the area for his first league goal for unbeaten Chelsea. The Blues were content to keep possession but were made to sweat in sealing a seventh win from eight games this term as Fraizer Campbell tucked in late on. It was at places like Palace last season that Chelsea’s title challenge faltered, but Jose Mourinho’s men are a different proposition this term and maintained their five-point lead over defending champions Manchester City. Chelsea face another test of their credentials at Manchester United next Sunday after the midweek Champions League clash with Maribor. John Terry started as Chelsea captain for the 500th time, having scored the own goal in March which saw the Eagles claim their solitary win over the Blues in their previous 14 meetings. Mourinho insists this term the Blues have the “balls” lacking at Selhurst Park seven months ago after beginning the season by dropping two points. Palace were prepared to test the theory, applying early pressure, with Campbell and Yannick Bolasie causing trouble for the visiting defence.