Chelsea 2-1 Queens Park Rangers

Chelsea have won all four games Oscar has scored in this season

• Chelsea stay four points clear at top of table

• Costa returns after four-game absence

• QPR's Austin scores his fifth league goal of season

• Hoops have lost four of last five league games

Leaders Chelsea moved nine points clear of title rivals Manchester City as a sublime finish by Oscar helped overcome a determined QPR at Stamford Bridge.

The Brazil midfielder lashed home a first-time low, angled drive with the outside of his boot from 12 yards after being set up by Cesc Fabregas.

Charlie Austin levelled when back-heeling Leroy Fer's shot into the net.

But Eden Hazard's penalty, after the Belgian was fouled by Eduardo Vargas, won it for Chelsea.

Premier League champions City will reduce the gap to six points if they beat neighbours United in the Manchester derby on Sunday.

Jose Mourinho's side head to Slovenia for Wednesday's Champions League group game against NK Maribor unbeaten in 15 games in all competitions this season.

They also have Diego Costa leading the attack again, the Spain international showing flashes of his best form against QPR on his return from a four-game absence.

Chelsea, though laboured, dominated possession and would have won by a more handsome margin but for several saves from Robert Green.

Their winner came with 15 minutes remaining, Hazard sending goalkeeper Green the wrong way from the spot after Vargas's foul.

It was hard on tireless QPR, who thought they had secured a point when Austin provided a moment of inspiration to divert Fer's shot, which was going wide, past Thibaut Courtois in the 62nd minute.

The main talking point of a highly competitive London derby was Oscar's goal-of-the-season contender in the 32nd minute.

It came soon after England international Green asked referee Mike Jones for the floodlights to be switched on as he was struggling to see clearly.

But he could do nothing as Oscar beat home with an early shot after Fabregas wrong-footed Yun Suk-young, his ninth assist in 10 league games since his £30m summer move from Barcelona.

Chelsea manager Jose Mourinho:

"My team didn't play well or well enough or so well as I was expecting. I was expecting more."

On Oscar's goal: "The goal is not impossible in a very talented boy.

"For 90 minutes I think he was our best player. Not for the goal, but for the dynamic, for the intensity, for the transitions. He was always sharp."

QPR manager Harry Redknapp:

"It's difficult to come here because Chelsea have so much talent, so much ability, so much strength.

"I felt we deserved something for how hard we worked. When you work that hard and don't lie down against the best team in the country, for that we deserved a point.

"We have to work as hard as that every game if we're going to pick up points and get out of trouble."

Chelsea and QPR players observed a minute's silence before kick-off in what was the last game at Stamford Bridge before Remembrance Sunday

Defender Branislav Ivanovic, who has two league goals for Chelsea this season, wasted a great chance when the game was goalless

Oscar has 15 Premier League goals since joining Chelsea in the summer of 2012

Charlie Austin has scored 24 league goals for QPR since the start of last season - including play-offs - 18 more than anyone else

Eden Hazard has converted all eight penalties that he has taken in the Premier League