Former Old Trafford captain says his old club's stronger overall squad could fall in their favour in European final despite Barcelona having the stronger starting line-up
Keane was part of the treble-winning United side in 1999 that dramatically beat Bayern Munich in Barcelona’s Nou Camp and they now face Pep Guardiola's side at Wembley later this month.
The former United captain maintains Sir Alex Ferguson's stronger squad could work in their favour.
“At Wembley, the United fans will take over the stadium. In a one-off game, with fans behind them, of course they can do it,” Keane told the Daily Mail.
“They will have to do really well to beat this Barcelona team and my concern would be not picking up injuries.
“The Barcelona starting XI is brilliant, outstanding, but their squad is probably not as strong as United’s.
"If they come through the end of their season fit, and they might get to rest players if they wrap up the Spanish league, they can rest United and would do well to get a result."
Keane has also stated that he is ready for a return to football management, four months after leaving Ipswich Town.
The former Sunderland boss was sacked from his position at Portman Road in January after a poor run of results and he has a clear vision of what he wants wherever he takes a job.
“I want a club to take to the very top,” Keane added.
“Sunderland was so close, even in my third season there, we just had a few poor results which every manager goes through.
“I am a young manager, and you are always learning tactically.
“I would have to look at my staff, that is a vital part of football management and you need to work with good players, that helps.
“And we had some really good players at Sunderland. You need good characters.
“I would learn from my mistakes particularly at Ipswich and I think potentially I could be a good manager.
“But potential is one thing. Going out and doing it is something very different. If you don’t make mistakes, you never learn.
“I had a three month break after Sunderland and Ipswich felt right. My only regret is I agreed to take it before I met the chief executive, I won’t be doing that again.
“Sometimes the DNA doesn’t work and doesn’t suit. Look at Roy Hodgson, and I’m not comparing myself to him, but him at Liverpool, the dynamics were not right and Ipswich in the end was just not right and the chief executive role is vital when you are working with someone so closely.
“I have been out for a couple of months and I am enjoying my bit of time off because part of my problem, is when I am involved, I am involved 100 per cent and that takes its toll on you; not that I am going to keel over but it is time to re-charge the batteries and take stock and see what is round the corner.
“A club might give me an opportunity but if it doesn’t come I have some freedom and I will make the most of that.”