His players were celebrating down the hall, invoking loudly the message of prevailing through a "siege mentality".
The Dundee United manager faced hands bristling with tape recorders. He was far from beleaguered. The opening question was leading: Ally McCoist had said his team were the better on the day?
"I'm not really interested, I'm just delighted to be in the final," he said. There was no protest, no irritation, just a flat declaration of fact.
He was also blunt in his assessment of the match.
"I thought Rangers would cause us problems at certain points in the match, but not through open play. I thought we were comfortable in open play," he said.
The message was that McNamara had anticipated the problems but his team had won through. The biggest challenge to his side - and one that McNamara would not admit publicly - was the demand of coming to Ibrox and trying to beat Rangers in front of 30,000 of their fans.
Would his young players freeze? Would flair and touch be blown away on a tempestuous day?
McNamara quietly played down the stress. "I put pressure on myself anyway as a manager," he said. "There isn't anything else on top of that because of who you're playing or where you're playing. There was a chance to get to my first cup final as a manager and that was my only thought - not getting one over anybody else, or where you are or the surroundings."
There were hints from the players, though, that the pre-match hype had taken its toll. John Rankin, the experienced midfielder, spoke of the "siege mentality".
"I don't think words can explain how it feels. Going to Ibrox, we knew how difficult it was going to be - and, let's not pretend, it was a home game for Rangers," he said.
"We used that to our advantage, developed a sort of siege mentality, saying everyone and everything was against us, saying 'let's go and prove what we can do'."
He added: "People were questioning the bottle of our young boys and, until Friday night, we didn't realise how few had actually played at Ibrox. It wasn't a lot.
"But I don't think you can question the bottle of our young players when you look at that performance. John Souttar and Ryan Gauld are 17 and 18 respectively, they played in the semi-final last year at Hampden and obviously put that experience into practice against Rangers."
A late arrival at Ibrox because of traffic problems also helped in that there was little time for morbid contemplation. Gavin Gunning, the central defender, later echoed his manager's statement of how "comfortable" United felt during the match.
The reality is slightly more complicated but it speaks well of United. This was not a commanding performance by McNamara's side. They were scarily vulnerable to the high ball from set pieces or, launched from deep, they found it difficult to dominate possession as expected (winning 51% to Rangers' 49% ), and their link-up play was intermittent and tentative.
There should be no surprise in this. This was a semi-final burdened with both expectation and tension for United. They were the favourites and they would have been confronted with loud and insistent criticism if they have been beaten by a team in the third tier. These accusations would have included underachievement and lack of "bottle". They would have made no reference to the weight of budgets that tilts heavily towards Rangers.
The crucial elements of an absorbing afternoon were that United wobbled on occasion but they never broke. Their best player was Paul Paton, who has a penchant for the destructive rather than the creative, but United were well served in moments by their more obvious talents. The vaunted "front four" all contributed something vital.
Gary Mackay-Steven stretched Rangers and scored; Stuart Armstrong was physical and scored; Ryan Gauld withstood pressure and brilliantly created the opening for the second goal; Nadir Ciftci was belligerent, strong and scored.
Gunning, who said talks were continuing with his agent over where he would play next season, was noncommittal over whether he could be a Rangers player. He was more precise in his assessment of his team-mates.
"There's been too many games this season where we've just been too easy to play against," he said. They were ultimately both resolute and successful on Saturday.
A year ago in the William Hill Scottish Cup semi-final against Celtic, United were brilliant. And lost. On Saturday, they were just good enough to win.
One does not have to be an intimate of Mr McNamara to divine which outcome he prefers.