United have lined up the Real Madrid superstar as a shock summer transfer target - although it now appears they won’t get their man.
But if they do, former Sky Sports pundit Keys reckons they’ll win the Prem title.
He said: “With Gareth Bale, United win the title. Without him they are strong contenders, who could muscle their way back to the top, but they're not nailed on.
“It's a shame to be talking about a United team 'muscling' their way to success, but that's what they are now - big and strong.
“Mourinho once said you can't win a title with less than five players over 6'2" because you're always vulnerable at set-pieces. Well he's fixed that little problem hasn't he?
“I fancied them strongly last season but the decay was worse than even I had been telling United punters - not that any of them ever listened.
“I repeat, Fergie got out at exactly the right time - and he knew it.
“He won the title in his last season, but the rot had already started. I said they needed eight to be competitive the following season and they've since spent £587m - I rest my case.
“So it's United for me - with Bale.”
Mourinho is still hoping to make one more summer addition and admitted in the build-up that he would "fight" for Bale if he was not involved in the Super Cup last night
Real Madrid head coach Zidane's pre-match coyness did little to quash the chatter, but naming Bale in the starting line-up did.
The 28-year-old produced an impressive performance from the outset, hitting the bar and setting up Isco for the second goal.
"Clearly the club wants him, the manager wants him and he wants the club, so for me it's game over - even before it started," Mourinho told BT Sport.
"It's game over clearly because everybody knows he is going to stay."
Bale was the subject of the most attention before and after the match given the ongoing speculation - talk he says has not thrown him at all.
"I am not listening to anything, I don't read anything, obviously I get told bits and bobs," the Wales international said
"I am enjoying my football here, I am playing as much as I can and I'm winning trophies so that's all I am concentrating on.
"I haven't had any conversations (with Madrid), I am just concentrating on my football. I'm trying to get my fitness up as much as I can after pretty much not playing regularly for eight or nine months.
"It is great to keep adding to the (medal) collection. It was a very difficult game but we got the job done and we've got another trophy and we move on."
