A few hours later, in the grounds of the England team hotel, Keegan was running through the injury list, a pre-match custom for every England manager since Walter Winterbottom. "It's an opportunity to play someone else," he said, "a chance to play another way. It might be a turning point, it might be the best thing that has ever happened."
It did not take long, watching Keegan at work yesterday, to realise that the quality he will bring most to the role of caretaker national coach is enthusiasm. It may only carry an international team so far but, the way England have been performing of late, it is just the tonic needed.
There are understandable reservations about the quality of Keegan's tactical sophistication, concerns he himself appreciated when he said: "I'm not your man for a 0-0 draw in the Ukraine." However, the immediate task is beating a moderate Polish side at home and any England team should be able to manage that if it is in a positive frame of mind.
This team should be. Not many of his England predecessors would have viewed an injury list which includes Darren Anderton, Robbie Fowler, Chris Sutton, David Seaman, Nigel Martyn and, most of all, Michael Owen, with Keegan's equanimity but his attitude will breed confidence among his players.
"He's so full of enthusiasm," said Ian Walker after training yesterday. "His love for the game shines through and rubs off on everyone else."
"I'm excited," said Keegan. "Working with these players is like being a kid in a toy shop. I'm delighted with the atmosphere. We have injuries but by Thursday night [when Keegan will make a final decision on the injured players] I'll still be able to pick a fantastic England team."
That team is unlikely to include Owen, who has not trained since straining a hamstring at Derby 11 days ago. Fowler took a knock on the knee in the same game and, with Sutton suffering from a back problem, Keegan's forward options are so limited he may call a replacement in tomorrow.
On the plus side David Beckham's calf problem and Nigel Martyn's back injury had eased enough for them to take part in yesterday's training session at Bisham Abbey but Anderton (groin) and Seaman (shoulder) also sat it out while Tony Adams appeared to be suffering from a heavy cold.
None of this prevented a lively session in which Keegan played a more peripheral role than expected. Howard Wilkinson, the FA's director of coaching, and Derek Fazackerly, Keegan's former coach at Newcastle, did most of the technical work, with Keegan preferring to do individual tuition or take a supervisory role along with Arthur Cox, his managerial mentor and the other member of his England coaching staff.
That was until the 10-a-side match which closed the session. Then Keegan was as involved as anyone, although he had mixed feelings when a neat turn by Steven Gerrard, the young Liverpool player with the squad for experience, left him bemused.
The media found it less easy to fool him. Drawing on more than a decade's experience in the trade, he said all the right things: It would be "a blow to lose any player" but no one would be risked unless they were fully fit; "I've been amazed at the co-operation from other managers"; "I felt proud when I pulled on my tracksuit and looked at the badge." Interestingly he also said that he "always thought he would be England manager one day."
In a refreshing change to his predecessor, Glenn Hoddle, he appeared to be honest when talking about injuries and open when discussing players' merits. Of Beckham he admitted: "I've always said I think he should be more involved and I think in the future he will be more central but, with a view to Saturday, he is in such good form playing wide for Manchester United, putting in such good crosses. Where I have got an opportunity is that I have Ray Parlour who can also play wide right or in midfield. They may be similar but don't rule out them both playing."
With Paul Ince suspended, David Batty injured and Nicky Butt not called up - a curious decision; Keegan said he was "close" - Keegan is short in midfield and may even give both Parlour and Tim Sherwood debuts.
He said: "In an ideal world you would like someone making a debut to look alongside and see someone with 30 or 40 caps. I know I would have preferred that. But this is the real world so I could say to them, `you're both playing at the top level; you're both in wonderful form'."
Keegan's playing experience in the real world in 1972 suggests he will not throw Parlour and Sherwood in together. Keegan made his international debut alongside Martin Chivers and Rodney Marsh, who had 12 and five caps respectively, played twice and was then dropped for 16 months.
So Paul Scholes, or Jamie Redknapp, is more likely to take one central place but Keegan added, with a typical flourish: "Why not play them both? They'll learn something, we all will, it might be very positive."
Keegan's reign may be short, but it will be eventful.