Five years ago, Mourinho brought his unheralded FC Porto side to Old Trafford in the second-leg of a last 16 tie and left victorious.

Mourinho got the Chelsea job on the back of a European triumph with the Portuguese club and subsequently defeated United in the Premier League, Carling Cup and 2007 FA Cup Final.

There were a couple of defeats as well but largely Mourinho has emerged triumphant in his head-to-head clashes with Sir Alex Ferguson.

So, as the Premier League leaders square up to their Serie A counterparts in the San Siro on Tuesday, the Inter coach is feeling quietly optimistic.

"I have so many good memories because we beat them with Porto," Mourinho told MUTV.

"Porto was not a big team - but we did it. With Chelsea we had a lot of good moments as well.

"When you play against Manchester United you cannot expect to win every time. Sometimes you draw and sometimes you lose.

"But my personal record is quality and it gives me a bit of extra confidence looking ahead to this tie."

While Mourinho can only hope the result goes Inter's way, he does know whatever the outcome he will have a friendly chat with Ferguson once the battle is over.

While the United boss has been at odds with Arsene Wenger so often during the past decade, his relationship with Mourinho has always been regarded as more than cordial.

It is one of the reasons why many pundits feel Mourinho will end up replacing the Scot at Old Trafford one day, although for now, the former Chelsea boss is happy with the situation.

"My relationship with Sir Alex is great," said Mourinho.

"Even when we were rivals in England the relationship was always good.

"The thing I like is that after the game, no matter what the result, we always had time to share a few minutes with each other and have a joke. I don't like relationships that change when you win or lose.

"There was always a real war when we played because we both wanted to win but afterwards it was good."

However, Mourinho knows it is not Ferguson that needs to be stopped but United's players, in particular fellow countryman Cristiano Ronaldo.

The Inter chief might have ruffled a few feathers earlier in the season when he claimed Zlatan Ibrahimovic was the best player in the world rather than Ronaldo.

However, the respect is genuine, even if Mourinho sees little point in deploying one man to try and mark the Ballon D'Or winner out of the game.

"Cristiano is a top player," said Mourinho. "I don't think he is someone you can stop with just one man. The team has to defend very well. That is what we must to do on Tuesday."

Ronaldo's brilliance is just one aspect of the United squad that has improved since Mourinho was controversially sacked by Roman Abramovich.

Ferguson has pieced together a team that appears capable of winning every trophy on offer.

Some are easier than others though, with Mourinho pointing out the small margins - in this instance John Terry's failure to convert a penalty that would have given Chelsea the trophy - that mean the difference between winning and losing at the highest level.

"I don't like the word lucky," said Mourinho.

"United won the trophy last season and they deserved it.

"But it is all about details. Last year, the details were on Manchester United's side."