“Bye guys. You need a lift?” Jose Mourinho asked the journalists before taking his leave of the Saint-Etienne press conference room late on Wednesday. “Is there space on the plane?” he then asked his press secretary with a look of mischief on his face before answering his own question. “No.” The laughter followed him out of the side door.

After an autumn in which the Manchester United manager was irascible, tense and in a state of permanent conflict with the “Einsteins” as he called us, the mist is lifted and normal service seems to be resuming. The win in the Massif Central on Wednesday made it 113 days since his side were last second best, with the League Cup loss at Hull City in that period not enough to halt their advance to Sunday’s final.

It is the defensive component that Mourinho has done most to restore, just as he did when first arriving at Chelsea in 2004, when Petr Cech promptly went 1,025 minutes without conceding (a record at the time). United have scored fewer goals than any side in the Premier League top seven but not since the heavy defeat Chelsea inflicted last October have United conceded more than one goal in a game.

Jose Mourinho issues instructions from the sideline during United's 1-0 victory over Saint-Etienne (Getty)

There have been winners – Henrikh Mkhitaryan, Chris Smalling – and losers - Wayne Rooney, Luke Shaw – in the survival-of-the-fittest contest now beginning to shake out and then there are the Machivellian mind games designed to foster that siege mentality. The level of public pre-calculation Mourinho displayed this week was extraordinary. Not only was he ready with his detailed fulmination when asked about some fixture congestion up ahead but had some poison to lay down for Manchester City fielding weak sides, too. “We are not Manchester City. We are Manchester United.”

It was the old Mourinho incarnate – playing to the gallery while deflecting talk away from a decision to play a full-strength team in France, which weakens him, with Mkhitaryan and Michael Carrick injured this weekend.

This is how it is with him and cup competitions, though. No manager has displayed a greater desire to win every one more than he and it explains his near faultless record in cups: nine victorious finals out of ten across Europe, including three League Cups out of three within these shores. No manager has a better 100% success rate in Sunday’s competition and it will certainly not have escaped his attention that he can equal Sir Alex Ferguson and Brian Clough’s record four League Cups on Sunday. These details matter to him deeply.

Mourinho has intuited more than any manager in the modern era what lifting the League Cup means. The first time he claimed it was the 3-2 win over Liverpool – his first Chelsea trophy – and the first signs of his siege mentality were in evidence on that occasion, 12 years ago this weekend.

Chelsea had just lost in the FA Cup at Newcastle and Champions League at Barcelona, prompting Arsene Wenger and Sir Alex Ferguson to predict that his team would be encountering turbulence. "Do Ferguson and Wenger want to change their position with me? Mourinho said, not bothering to disguise a smile. When Liverpool’s fans booed him that day, he put a finger to his lips. The win, under the shut roof at Cardiff’s Milllennium Stadium, brought Chelsea’s first trophy in five years and unbridled Mourinho delight. You sense that the significance of that February day has maintained his absorption with what Liverpool’s Phil Thompson once called ‘the Mickey Mouse Cup.’

He wins in this much-derided competition by selecting near full-strength teams and always – always – obsessing about the opposition. The former fringe Chelsea defender Steven Watt tells writer Ciaran Kelly for his Mourinho study ‘The Rise of the Translator’ how astonished Mourinho’s charges were to find him analysing the entire starting XIs of obscure sides. “It was treated with the same respect as if it were a Champions League game.”

Mourinho, and Man United, haven't underestimated any competition this season

The same will apply to Southampton, who are looking for their first silverware since the legendary 1-0 win over United in the Bobby Stokes final of 1976, and though Claude Puel’s side carry the romance of that memory and two clear weeks of preparations, they have won one of their last four matches, including the 5-0 defeat to Arsenal in the FA Cup. Their own progress to Wembley has also been built on defence. They have not conceded a single goal in 450 minutes of football en route to the final.

The probable absence of Mkhitaryan, United’s most creative player, is a blow, as is Michael Carrick, also injured at Saint-Etienne, since United’s win ratio falls from 75 per cent to 55 per cent without him. Marouane Fellaini may partner Ander Herrera at the back of midfield, with Paul Pogba behind Zlatan Ibrahimovic. Southampton’s key absentee - Virgil van Dijk – seems more significant, though, as Southampton have conceded 10 goals in five games since he developed ankle problems.

Buried in the politicking of Mourinho’s departing words at Stade Geoffroy-Guichard was the essence of how and why he has put together something which seems increasingly to be feared. “It is nice in four months to have only one little defeat, a defeat where we could have that defeat because it was two legs,” he said, sounding the soul of modesty. “It’s nice. It’s a good feeling. We trust in each other.”

Possible teams

Manchester United (4-2-3-1): De Gea; Valencia, Bailly, Smalling, Blind, Fellaini, Herrera; Mata, Pogba, Martial; Ibrahimovic