Despite enduring a season they will quickly want to forget, Chelsea again managed to stick a sizable thorn in the side of Arsenal’s title chances with Diego Costa’s goal securing the visitors a 1-0 victory at the Emirates Stadium. Costa had been the pivotal figure in the London rivals’ last meeting in September, when Arsenal saw two players sent off. And he was influential once again on Sunday, although this time it was his football, rather than his temperament, that took center stage.

It was the Spain striker who was crudely brought down by a desperate lunge from Per Mertesacker just 18 minutes in as he burst clear of the Arsenal defender and eyed up a clear path to goal. A red card was duly produced, and just minutes later, while Arsenal were still reorganizing, Costa skillfully and determinedly turned in Branislav Ivanovic’s inviting cross at the near post.

By that point Arsene Wenger had already removed Olivier Giroud, to plenty of bemusement from the Emirates crowd and the Arsenal striker himself, in order to bring on a replacement center-back in Gabriel. But, despite continuing to have plenty of the ball with a man disadvantage, and welcoming Alexis Sanchez back from injury in the second half, Arsenal could not find a way back into the game.

The defeat extends Arsenal’s miserable run against their London foes to just four wins in their last 24 Premier League matches, and none in their last nine. No side has exploited Arsenal’s lack of title-winning steel in recent years more than Chelsea, meaning it was easy to see why, even with Jose Mourinho’s departure and Chelsea’s woeful season, Wenger had earmarked this as another big test for his side.

Yet, as they seek to end their 12-year-long title drought, it is one they have again failed. And it is now three matches without a win for Arsenal, which sees them drop from first to third in the Premier League table, three points behind Leicester City, level on points with Manchester City and only two clear of Tottenham. A four-way tussle for the title now looks a very real possibility.

For Chelsea, any thoughts of retaining their title have long since gone. Instead this win has eased any lingering fears of being sucked into a relegation battle, with the three points taking them up into 13th place, seven points clear of the bottom three.

It was a performance that again provided evidence of Hiddink having steadied the rockiest of ships since replacing Mourinho last month. And it is now seven matches unbeaten in all competitions since the veteran Dutch coach assumed the reins for the second time. One of his biggest achievements has been to get Costa again focusing more on his activities with the ball in the opposition penalty box than provoking his opponents.

Costa had been given a retrospective three-match ban for his altercation with Laurent Koscielny in September. And there was an early flicker of lingering hostilities on Sunday, but Costa’s football did the damage on this occasion. His eagerness to run in behind the Arsenal defense was a threat throughout his time on the pitch, before exiting with an injury in the second half. And it was one of those surges that caught out Mertesacker for the crucial moment of the match. Five minutes later, he got himself in between Koscielny and Gabriel to leave former teammate Petr Cech with no chance.

Chelsea had chances to extend their lead. Before halftime, Costa forced Cech into a solid save and Ivanovic had a header cleared off the line. Meanwhile, in the second half Cesc Fabregas had a strong appeal for a penalty turned down.

Yet for most of the remainder of the contest, it would have been hard to decipher which team had the man disadvantage. Chelsea remain some way short of the devastating force of the start of last season, and lacked the decisiveness to capitalize further, allowing Arsenal to control large portions of the contest.

Yet the decision to remove Giroud came under question as Arsenal missed a real threat in the opposition penalty area. There were brief sights of goal, but Mathieu Flamini volleyed over from the center of the box right at the end of the first half and then a series of Arsenal players failed to get a clean strike away during a penalty-box scramble following a second-half free-kick.

Wenger will surely claim that the red card changed the game. And, indeed it did. But there could be no real question of the validity of the decision, or that, ultimately, two defensive lapses have cost Arsenal vital points.