Costa, who was not called up for Spain’s last two games so he could rest, netted his 11th goal in 10 matches in the 11th minute.

Oscar passed to Costa and the former Atletico Madrid striker hit a right-footed shot from middle of the box into the left corner of the goal.

The second goal came after a Chelsea corner.

Cesc Fabregas, who started despite being an uncertainty for the game because of a hamstring problem, set up Hazard and he drove a left-footed shot from the six-yard box into the left corner of the goal for the Blues’ second.

Just four minutes later and West Brom’s challenge became more difficult when Claudio Yacob was shown a red card.

The victory put Chelsea on 35 points – 10 clear of Southampton, who play at Aston Villa on Monday.

Manchester City climbed into second place on 27 points after coming from behind to defeat Swansea at the Etihad Stadium.

Wilfried Bony gave the visitors a 1-0 lead just nine minutes into the contest.

He scored from the centre of the box after chesting down Nathan Dyer’s pass before finishing neatly.

The goal was the first ever scored by Swansea at the Etihad.

The Blues needed just five minutes to pull level with a goal from Stevan Jovetic.

Jesus Navas set up Jovetic, who drilled a right-footed shot from close range past goalkeeper Lukasz Fabianski.

After Gael Clichy hit the bar for the home side, Fernandinho back-heeled the ball into the path of Yaya Toure in the 62nd minute and he smashed it in for the winner.

The victory was just what Manuel Pellegrini’s squad needed ahead of their Champion League clash with Bayern Munich on Tuesday.

A win would have allowed Swansea to leapfrog West Ham into fourth place because the Hammers slumped to a 2-1 defeat at Everton.

The Toffees went in front with a 26th minute strike from Romelu Lukaku.

Mauro Zarate, who came on as a substitute for the visitors six minutes into the second half, equalised in the 56th minute.

His goal had a touch of good fortune because the ball glanced off Phil Jagielka and went over keeper Tim Howard.

Midfielder Leon Osman then celebrated his 400th appearance for Everton when he slid in and hit a low cross from Samuel Eto’o on a counter-attack, with the shot beating West Ham goalkeeper Adrian.

Newcastle won for the fifth straight game and leapfrogged Swansea and West Ham into fourth place in the Premier League table after getting a 78th minute goal from Moussa Sissoko against QPR.

The Magpies, in the lower echelons of the standings in the first couple of months, are now flying high while QPR are now at the bottom of the table with just eight points from 12 games.

Burnley, meanwhile, are off the bottom after getting a pair of first-half goals in quick succession from Danny Ings at Stoke.

Ings notched his first in the 12th minute when he tapped in after Asmir Begovic parried a cross from Ashley Barnes.

He then scored his second in the 13th minute after being set up by Michael Kightly.

Jonathan Walters headed in a goal for Stoke in the 32nd minute, but the visitors prevailed 2-1.

Burnley are now third bottom, level on 10 points with Leicester after the Foxes ended up with a goalless draw at Sunderland.

Leicester had chances to score through Jeffrey Schlupp and Matt James but the club have gone five consecutive games without hitting the back of the net.

They have claimed just two points from the last 21 up for grabs.

Sunderland’s best chance to break the deadlock came when Steven Fletcher got a shot on target from close range but was denied by Kasper Schmeichel.