After the 1-0 victory at the Estadio do Dragao, Sir Alex Ferguson pointed out something fairly obvious.
“If we get back to that foundation of not giving away goals then we can do well,” he said.
The second leg performance against Porto was hardly earth-shattering. Even those who performed well constantly gave the ball away and wasted good opportunities.
But, where Porto had exploited United so easily at Old Trafford, they struggled to create chances all night on home turf.
"I couldn't see the dangers,” Ferguson continued. “I thought we controlled that part very well. Nothing really bothered us."
United barely created anything themselves but, after Cristiano Ronaldo had put them in front in spectacular style so early on, it didn’t matter. What mattered was that they were able to effectively shut up shop.
It was more or less a replica of the showing against Barcelona in the semi-finals last year, when Paul Scholes struck a similar long-range effort before United simply prevented either side playing.
However, what remains to be seen is whether they can do that again when they face the world’s very best sides.
Ferguson credited the return of the Ferdinand-Vidic partnership for the success against Porto, but Owen Hargreaves has been seen as the missing link during the dark times in the United defence.
(Yes, United broke records this season, but were they really as good as the stats suggested? There are lies, damned lies and statistics after all, and there were more than a few shaky moments during that run.)
Anderson did plenty of good work in the Hargreaves role on Wednesday, but the suspicion remains that he’s still a little lacking in experience. Against Porto, much of his good work was undone by careless play, giving away possession when he could have kept it simple.
As a side that has started to become viewed as vulnerable, the uneventful 1-0 win in Portugal was, in many ways, the performance United needed to restore confidence.
But Porto didn’t provide a stern enough test to suggest with any certainty that that was truly the turning point.