It is rare for Sir Alex Ferguson to appear bewildered but this was a bewildering game. For the eighth time in a dozen matches Manchester United had fallen behind. For the third time in seven games at Old Trafford, they had conceded early.
"I don't know, I just couldn't tell you," he said, when trying to analyse United's defensive frailties. "The goals we have lost haven't come from one area or one direction. We keep conceding early. I can tell you that."
In many ways Tuesday night's 3-2 Champions League group victory over Braga was an archetypal United game. They start badly, they concede early, they fight back and usually force themselves over the line in the generous minutes of "Fergie time" the referee has allocated.
Against Bayern Munich or Barcelona this would be considered heroic. Against a team that is not one of Portugal's big three it appears rather worrying. What has perplexed Ferguson most of all are the displays at Old Trafford, the one ground in England that most fits the commentator's cliché of "fortress".
United have kept only two clean sheets within its walls this season. These were against Galatasaray, who struck the frame of their goal three times, and Wigan, a club that has managed a single goal in the stadium in its history – and that a penalty.
In many ways it is obvious why United are struggling defensively. The answers lie on the treatment tables at Carrington, where Chris Smalling is starting his rehabilitation from a broken metatarsal and Phil Jones from a chronic back injury.
Last season, when United were deprived of their captain, Nemanja Vidic, Smalling and Jones performed well enough for the team to take the title race to Sergio Aguero's last kick of the campaign.
Once, Rio Ferdinand and Jonny Evans might have been enough. The Ulsterman is fulfilling all the promise that made Roy Keane so desperate to make his loan move to Sunderland permanent, and that made Ferguson so anxious to reassure him of his future in Manchester. In the Estadio do Dragao he gave a masterful performance to earn Northern Ireland a 1-1 draw against Portugal.
However, Ferdinand will be 34 next month and there have been too many injuries. In former times Ferguson would have played him on Tuesday night against Braga and on Sunday at Stamford Bridge. No more.
Instead, there was just Michael Carrick filling in, but he is a midfielder for a reason and this was like asking Sid James to play Macbeth. Braga were two up after 20 minutes.
Ferguson has detected a change in the way opponents take on teams like United. Once, they would counter- attack with one or two forwards. Now it is in numbers and at speed. He noted that last month Galatasaray had scored a goal against Braga that took nine seconds from the move beginning to the goal being scored. The move went the length of the pitch and was finished by the man who started it.
However, United's problems extend beyond their back four. Traditionally, they have been a club that has embraced wing play but, with Shinji Kagawa and Robin van Persie having to fit into a side that pivots around Wayne Rooney, they are evolving into a diamond formation.
"It is revolutionary because it is going against our history," said Ferguson before the breathless encounter with Braga. "But the game in Europe and England is now at such a high level that making yourself unpredictable is going to be a strength."
The last time there was such a radical overhaul of tactics was in 2001 when Ferguson spent nearly £50m pairing Juan Sebastian Veron and Ruud van Nistelrooy, abandoning the 4-4-2 that had won the European Cup two years before. He also sold Jaap Stam and gambled on the 36-year-old Laurent Blanc, who would supposedly bring on young defenders like Wes Brown and John O'Shea.
Nothing about that really worked. Then as now they produced some astonishing comebacks, overturning a three-goal deficit to stupefy Tottenham at White Hart Lane. Then as now they were vulnerable at Old Trafford, where they lost five times in the league, falling unfamiliar victims to Middlesbrough and West Ham. Then, they did not win the title. And as for now?