ARSENAL 0 CHELSEA 2: Those "psychological effects" of which Arsene Wenger had spoken when considering the significance of this collision between the Premier League's top two may now be afflicting his Arsenal squad rather than bolstering them.
Chelsea crossed London to claim this tie and a place in the League Cup quarter-finals with relative ease. They were more streetwise, more powerful and certainly cannier in key areas, their victory achieved with a goal in either half and plenty to spare. It all seemed far too comfortable.
Wenger has yet to overcome a Mourinho side, the Portuguese having now extended his mastery over Wenger’s Arsenal to nine games.
The league meetings between these teams may prove to be tighter but for now, with one route to a rare trophy now blocked, Wenger will be experiencing a familiar frustration.
This derby had been lent greater significance by the two teams' lofty status in the league table, even if both managers had, as anticipated, radically shuffled their packs.
While Arsenal's selection offered the mix of youth and experience suggested by Wenger in the build-up, the visitors fielded only one player, Gary Cahill, who had started Sunday's victory over Manchester City.
Theirs had apparently been a protest selection, outraged as Mourinho was at having to play just 48 hours after that thunderous City occasion to fulfil TV demands, though the Portuguese would always have been tempted to deliver a lineup of personnel with much still to prove to the new manager.
He has tapped into their hunger before.
Just as at Swindon in the previous round, the likes of Juan Mata and David Luiz were offered game-time and while Chelsea's lineup may not have been first-choice, it still oozed class
The opening goal bore remarkable similarities to Fernando Torres' winner at the weekend, though while scored by a compatriot, its source was unlikely.
Chelsea had defended a corner stoutly with Mata calmly sending Samuel Eto’o upfield and the Cameroonian, in turn, slipping a pass to Essien. While Arsenal heaved to recover, the midfielder’s pass looped up from Ramsey’s challenge towards the home penalty area, bouncing and kicking up from the turf.
The retreating Wilshere spotted Carl Jenkinson’s intention to nod back towards the goalkeeper Lukasz Fabianski and bellowed out a warning, pleading with his team-mate to let him collect. As withMatija Nastasic on Sunday, the call went unheeded.
The rest was inevitable. Jenkinson's connection lacked conviction and Cesar Azpilicueta darted through on the blindside to poke his shot beyond the advancing Pole and in off the far post.
The second goal was gloriously taken, Eto’o hooking a throw-in back into the box, Willian nodding on and Mata taking a touch before slamming his finish beyond Fabianski.
Mata’s star has slipped, risen and dipped again this season.
This was a reminder that he remains a player of sumptuous talent, vision and finesse.