Arsenal fall for Costa's dirty tricks as Chelsea perfect the art of winning ugly.

He did not score either goal, but the hero’s reception for Diego Costa when he was substituted eight minutes from time told the Chelsea striker that he was the man who won this game for the champions.

It was Costa who had goaded Gabriel into the foolish retaliation on the stroke of half-time that reduced Arsenal to 10 men and completely changed the nature of the contest.

Costa is a player who attracts as much hatred from opposing supporters as he does love from his own fans - and this was a game that showed exactly why.

Costa and Gabriel had clashed less than a minute earlier after the Blues striker escaped punishment for thrusting an arm at Laurent Koscielny.

Had referee Mike Dean spotted Costa’s swinging arm, the Spain international might have been the one trudging down the tunnel early.

Instead, it was Gabriel after Costa roped him in to a needless flick of his studs following at least 30 seconds of the two men sparring verbally.

“Costa can do what he wants,” complained Wenger in his post-match press conference. “He has to stay on and everybody else has to be sent off.

“I think it’s unacceptable what he does to Koscielny, he pushed him in the face. I don’t understand how he gets away with it.

“He will do the same next week and the week after - and he will get away with it. He always uses provocation and he benefited from the naivety of my team today.”

He is a player in his manager Jose Mourinho’s own image. Costa is aggressive, confrontational and he crosses the line on occasions - but he is also someone you would want with you in the trenches.

From Arsenal’s perspective, Gabriel’s sheer naivety reflected the lack of leaders in this Gunners team - a point made time and again but never addressed by Arsene Wenger.

There was a time 10 or 15 years ago when Arsenal might still have fancied their chances against a top team with 10 men, but there was no belief here. It was always going to be an uphill battle.

The Gunners finished the match with nine men after Santi Cazorla’s red card for a second booking, but despite his protests the Spaniard can have no complaints once he sees the replays.

But by then, even with the score at 1-0, Arsenal looked out of the game.

In the 53rd minute, the goal came as Kurt Zouma headed home Cesc Fabregas’ lovely free-kick - and thereafter the result was never in doubt.

Alexis Sanchez missed a glorious chance to equalise when he latched on to a mistake in the Chelsea defence but mishit from close range.

It might have been a different story had that struck the net, but nobody was going to stop Mourinho’s men today.

Mourinho and Wenger shook hands before kick-off but there was no repeat at the final whistle.

While Wenger stormed down the tunnel, Mourinho embraced his staff and substitutes after a huge win for last season’s champions.

After back-to-back defeats against Crystal Palace and Everton, they had to win here to have any chance of retaining their title.

They played with purpose, aggression and concentration from the first minute. If the plan was to bully Arsenal, take the lead and then control the game, it worked a treat.

Wenger beat Mourinho for the first time in the Community Shield in August at the 14th attempt, but this result ensures that the Portuguese has restored the status quo.g