Jose Mourinho has tipped Sir Alex Ferguson to stay at Manchester United for many years to come.
The Portuguese 'Special One' is seen by many as the perfect successor to Ferguson when the 67-year-old finally steps down.
While Mourinho himself admits that Old Trafford now "feels like home", he hopes that the current United boss will stay for some time.
Speaking ahead of his side's UEFA Champions League clash at the 'Theatre of Dreams' on Wednesday - which will be screened live on Sky Sports 2 at 7.45pm - the Inter Milan boss said: "2004 was the first time I came to Old Trafford with Porto, so everything was new for me.
"But now it is like home because, in the five years since I first came here, I have been a lot of times in the Premier League, Carling Cup and FA Cup semi-finals.
"It has become part of my life and in that sense it's a different feeling coming back.
"I even know the groundsman. He is asking me to train on one side of the pitch because that side has no sun. I know the man, he's a nice guy, so that's okay!
"But succeeding Sir Alex? In 20 years maybe! He's tough, he's strong, he is happy and he loves it. He still wins, so let him be here for 20 more years!"
Mourinho inspired Porto to victory over United in the Champions League second round in 2004 as he guided the Portuguese club to the European title.
He admitted that Costinha's decisive injury-time goal at Old Trafford, which sparked his memorable dash down the touchline, paved the way for him to land his job at Chelsea.
"Because of that goal, we could win the competition. Without it, we wouldn't even reach the quarter-final," he said.
"A few years later, a lot of people knew those Porto players, but at that time they didn't. Who was this crazy manager running down the touchline?
"It was a crucial moment in our career. Our careers changed and that team was destroyed because everyone had the potential for different flights.
"That was the goal which opened doors in England for me and my career was never the same. Of course I remember that moment really well, but that's football, that's over and I'm not one to look back.
"On Wednesday, we will try to do it against a very, very good team. We have in mind what we have to do and we know our qualities.
"Football is football. You never know what will happen, but we are prepared for the game and we believe we can do it."