Nine matches, five defeats and so the wait goes on for an Arsene Wenger team to beat one managed by Jose Mourinho. At least this season, the League Cup does not represent the only realistic hope that Arsenal have for a trophy.
Wenger's side are still top of the Premier League. They have still played some of the most exciting football in Europe this season. They were, in terms of individuals, the weaker of these two mid-week League Cup XIs before a ball was kicked. Yet even so, the result said much about the depth of Chelsea's resources and the sheer bloody-mindedness of their manager to get a result in a tie that he has, at various points over the last few weeks, proclaimed to give up on.
When you can name Juan Mata in the second string, and when the Spanish No 10 comes up with a goal like the one he scored here, there is not much doubting the talent at Mourinho's disposal. Even so, he still has to marshal it effectively and Chelsea gave very little away, virtually nothing in the way of chances, while punishing Arsenal ruthlessly on the counter-attack.
It is Chelsea who are in the quarter-finals of the Capital One Cup, with a goal in the first half from right-back Cesar Azpilicueta and then Mata's beauty after the hour. Meanwhile, Arsenal were forced to rely on the inadequate Nicklas Bendtner in attack and suffered a Carl Jenkinson error to let Chelsea in for the first.
It is carelessness such as this that has cost them in the past and while the 2013-2014 version of Arsenal looks much more promising there was still some of the old weakness. Wenger could have gambled more on winning this game, but in the end his team risked too little and gained nothing. Worst of all, they looked vulnerable in the face of another Mourinho masterplan.
The team that Mourinho fielded can be valued in transfer fees at around £140m, around three times as much as the side Wenger picked. Neither manager selected extensively from their Under-21s, although it was Wenger's side that looked - on paper at least - the weaker.
There was not the core of homegrown young 'uns in the home team that characterised Wenger's side in the previous round against West Bromwich Albion. He selected Ryo Miyaichi in his starting team but chiefly it was players like Thomas Vermaelen, Nacho Monreal and Carl Jenkinson who have found their first team opportunities restricted this season.
Nevertheless, there was enough in the Arsenal side, including Aaron Ramsey and Jack Wilshere that they would have expected to make a better fist of it than they did. A goal down in 26 minutes, they never really forced Mark Schwarzer into a big save. In the first half a shot from Monreal from the left was deflected marginally wide by Gary Cahill's sliding block.
Wenger had picked a mixed bench, including Mesut Ozil and Olivier Giroud, as well as the lesser-spotted Ju Young Park and the 18-year-old Isaac Hayden. Mourinho also gave himself some options, with Fernando Torres, Eden Hazard, Ramires and Branislav Ivanovic among the substitutes. Once Chelsea had taken the lead, it was hard to see where Arsenal might prise the initiative back from the away side with Bendtner so anonymous.
Arsenal passed the ball beautifully at times, not least when they worked it left to right on 15 minutes, eventually winning a corner. But Chelsea, with Michael Essien and John Obi Mikel in front of the back four, were hard to break down and were gifted a goal on the counter-attack.
That attack might have broken down when Samuel Eto'o passed the ball inside and Essien was obliged to challenge Ramsey for the ball. From their collision it looped forward into the Arsenal box. Wilshere seemed to gesture to Jenkinson that he should leave the clearing up to the midfielder but the latter attempted a header back to Lukasz Fabianski which fell fractionally short and Azpilicueta nipped in to toe it past the Arsenal goalkeeper.
Azpilicueta? It was not immediately clear what the Chelsea right-back, out of favour this season under Mourinho, was doing so far forward other than he must have been blithely following the counter-attack. It was a neat finish for his first goal for the club.
Otherwise, Mourinho's regular bouts of touchline applause seemed to indicate that he approved of the way his defence kept the ball and passed out under pressure from Arsenal. The much-maligned Kevin De Bruyne was given a reprieve and, back in the team, was heavily supervised for the first half by his manager on the near touchline.
In the second half, it was only a matter of minutes after Wenger started to throw his resources at the comeback that Mata's goal put it out of the reach of the home team. In fact, Ozil, on as a substitute, had scarcely given away a foul on the edge of the Chelsea area then the away team, a rapid counter-attack unit all night, ventured to the other end and scored.
The second goal will go down as another pure strike from the right boot of Mata, but it was also the scrapping and the effort that got the ball to him on the edge of the area that marked out Chelsea's night. From a throw-in on the right to Eto'o on from a header from Willian to Mata who struck the ball with enough of the outside of his right to send it spinning away from the glove of Fabianski.
Steve Holland, a substitute himself for Mourinho in the post-match press conference, made the case that Mata has played in his “share” of the bigger games of the season. But there is no doubt he remains an understudy to Oscar in their preferred position. “What appears to be the team that's preferred at the moment won't be the team that's preferred in January,” Holland said, “and that will be different again in March, April and May. We need everybody.”
In the aftermath of the goal, Wenger sent on Giroud for Bendtner whose revival has become a theme of late at Arsenal. Not here, perhaps not ever. Although Bendtner has until January to make an impression when Wenger may well be forced into signing another striker. Unfortunately for Arsenal, the reliance upon Giroud was writ large as Bendtner generally laboured around the place to the annoyance of many of the home fans.
The strangest moment was when he was fed the ball by Tomas Rosicky in the area and seemed to be unaware that he was unmarked and able to turn to face goal. Instead he laid it off to Ramsey and the little patience that remained for Arsenal's Danish striker appeared to ebb away. Even Park was sent on at the end.
There was a warm handshake offered by Mourinho and accepted by Wenger at the end of the game, as there had been at the start. The Arsenal manager warned against snap judgements on his team following this defeat and last week's to Borussia Dortmund, but he could certainly do with a victory over Liverpool on Saturday to placate the fears that his side struggle against this season's leading teams.
Arsenal (4-2-3-1): Fabianski; Jenkinson, Koscielny, Vermaelen, Monreal; Ramsey (Park 82), Wilshere; Miyaichi (Ozil 63), Rosicky, Cazorla; Bendtner (Giroud 66).
Chelsea (4-2-3-1): Schwarzer; Azpilicueta, Cahill, Luiz, Bertrand; Essien, Mikel; De Bruyne (Ramires 67), Mata (Kalas 90), Willian; Eto'o (Ba 81).
Man of the match Mata.
Referee P Dowd (Staffordshire).