He was not indulging in amateur psychology aimed at his or the Inter players but was making a cold appraisal of the merits of the two teams. If he is right then United will go through to the semi-finals at the San Siro in a fortnight's time.
A goal for United - and you did not need to be the best modern manager in Britain to locate frailty in the much-vaunted Italian defence - will mean Inter will need four at home and, even if Ronaldo is fit, that is an unlikely and intimidating task.
Much hype has been circulating about Old Trafford's chances of conquering Europe this time but maybe luck, circumstance and talent are combining to allow Ferguson's time to come. At the very least, if United fall short this season there are no compelling reasons apart from not being good enough.
It was a theme picked up by Ferguson's captain, Roy Keane, as Wednesday turned to Thursday in an empty and echoing Old Trafford. "In the past we've either been too young, too inexperienced or had too many injuries but now we have to accept this is who we are. Tonight we began to show the maturity we've been searching for."
Importantly, rival teams are reaching that conclusion too. Inter, apart from a late flurry which should have yielded a goal, were disappointing but were forced into a shell by concern. They feared United's pace and fretted about Ryan Giggs and contorted their shape to counter both at the expense of their own flow.
Mircea Lucescu withdrew Youri Djorkaeff and Roberto Baggio to wide positions to cover the incursions of United's full-backs, but while the former supplemented Javier Zanetti to curtail Giggs, the latter's idea of tracking back was half-hearted at best.
The consequence was Aron Winter, a midfield player rather than a full- back, was frequently confronted by two players, Gary Neville and David Beckham. The answer would have been for the centre-back Francesco Colonnese to move across to aid Winter but Inter were so conscious of their aerial inability they did not have the confidence to let Giuseppe Bergomi and Fabio Galante go one on one with Andy Cole and Dwight Yorke.
The outcome was not edifying for anyone who has admired the rugged obduracy of past Italian teams. Beckham, who Ferguson described as the best crosser in Europe, was free to torture Inter with a series of precise arcs that led to two headed goals for Yorke and would have provided another for Cole but for an exceptional save from Gianluca Pagliuca.
Inter will devise a system to counter Beckham at the San Siro but his priorities will be different and more defensive there and United will be hitting on the break. Cue the pace of Giggs and Cole primed by Yorke's cleverness and the reason why Ferguson is so confident.
Yorke, who now has 24 goals this season, had arguably his best match for United while if Peter Schmeichel is still going through a crisis in confidence then he is going to freeze forwards with apprehension when he casts off his doubts, but it was Beckham who had Ferguson drooling.
"We gave him a rest for three weeks over the New Year and he's benefited from that," the United manager said. "There's a great freshness about his game and he's back to his peak performances, posing questions for every team he meets. He is an outstanding central midfield player but until I get someone who can cross the ball as well as that he'll stay on the right wing."
Ferguson has been criticised for rotating his squad but, as he pointed out on Wednesday, Beckham, Schmeichel, Gary Neville and Paul Scholes have had rests this season and all but the last, who flickered rather than shone, were outstanding against Inter.
Given the attention on Beckham, who was meeting Diego Simeone for the first time since his infamous sending off playing for England in the World Cup, it was a remarkable performance and one, glory be, that might be a sign of his growing up.
If you give him the benefit of the doubt that he did not flick out at Simeone in the first half and was merely spun round by the momentum of his tackle, it was a composed performance from Beckham, who was gracious enough to exchange colours and smiles with his St Etienne nemesis at the end.
"I decided before the game it would be a nice idea to swap shirts with Simeone," Beckham said. "There's been a lot said about me and a lot about him, there's been a lot of hype, but I have learned to get on with my life, I don't listen to what people say about me.
"It was a good night for me with two good crosses but the great thing for me is with Dwight Yorke and Andy Cole, one is always spinning away from the other and that means you've always got something to aim for. They make it easy for me."
Inter and luck made it easier for United, too, because there seemed little wrong with Simeone's disallowed goal and Ferguson's satisfaction would have been soured if Henning Berg had not cleared off the line from Colonnese in injury time.
"We will have to look at why those things happened towards the end," Ferguson said refusing to gloss over his side's deficiencies on a night of shuddering commitment where excitement might have dulled his critical faculties. "We can get better. I thought we were fragmented at times and the tempo of our passing could have been better."
Both faults stemmed from an unsure grip on concentration, which is United's enduring weakness, and if Ferguson can conjure an improvement in that department, there will be genuine reasons for optimism.
Inter have twice overcome two-goal deficits against English sides - against Liverpool in 1965 and Aston Villa nine years ago - but there was little on Wednesday to suggest they will do the same on 17 March. With or without Ronaldo.
n Ryan Giggs broke his nose in a collision with Javier Zanetti late in the game, but the injury is not expected to exclude him from Sunday's FA Cup quarter-final against Chelsea.