A SPECIAL strike from Oscar and an Eden Hazard penalty earned Premier League leaders Chelsea a 2-1 win in a hard-fought west London derby.

Striker Diego Costa returned following a four-game absence with his problematic hamstrings and showed few signs of rustiness as Chelsea took the lead through Oscar's classy goal.

Jose Mourinho's men were unable to build on the lead, though, and after Hazard's weak header, QPR broke to equalise through Charlie Austin's improvised finish with 29 minutes remaining.

Chelsea had only previously dropped points this term in drawing at Manchester City and Manchester United; another draw in Mourinho's first encounter with lowly QPR was almost unthinkable.

The hosts were saved when Eduardo Vargas bundled over Hazard 15 minutes from time and the Belgium playmaker netted from the penalty spot.

The win enabled unbeaten Chelsea, who play Maribor in Champions League Group G on Wednesday, to stay four points clear of second- placed Southampton and, more significantly, took them nine ahead of defending champions City.

City play United, 13 points behind, at the Etihad Stadium today, so have a game in hand, but last season's runners-up Liverpool are 12 adrift ahead of Saturday's clash with Chelsea at Anfield. QPR fell back into the drop zone after briefly climbing out following last Monday's defeat of Aston Villa.

Costa looked lively early on, teeing up Oscar, who scuffed a shot wide, before finding Willian whose cross was directed into the side-netting by Branislav Ivanovic.

Austin, scorer of both goals in the defeat of Villa, was thwarted as he met David Hoilett's cross when QPR briefly entered enemy territory before Leroy Fer's hesitation allowed Chelsea to snuff out another visiting attack.

Cesc Fabregas then won the ball midway inside QPR's half and shot, only to be denied by Rob Green as the visitors kept Chelsea at bay, but Mourinho's men struck soon afterwards.

Filipe Luis had the ball down Chelsea's left and play was switched by Fabregas, who ran with the ball, exchanged a one-two with Costa and then fed Oscar in the right side of the QPR area.

The Brazilian brilliantly hit a first-time shot with the outside of his right boot into the far corner for his fourth of the season.

Hazard was on the receiving end of a verbal torrent from Mourinho for failing to anticipate Oscar's through ball as Chelsea attempted to build on their lead after the interval.

However, after threatening several times, with the Belgian at the centre of much of their best play, the home side were pegged back when Rangers equalised on the counter-attack.

Thibaut Courtois palmed away Vargas's shot from the right, Fer mis-hit a volley from the edge of the area and Austin re-directed it in with his heel.

Green then saved an Oscar free-kick, but Chelsea were given a lifeline when Vargas clumsily barged Hazard over as the Belgian charged into the box. The winger took full advantage by rolling home from the spot.

Costa later took his leave, with Andre Schurrle coming on in his place, but Chelsea were forced to hang on for the three points as Austin had an effort blocked by Gary Cahill.