Cristiano Ronaldo has revealed winning the Champions League with Manchester United is still his “ultimate” achievement.

But Ronaldo has warned his former club he is determined to ­repeat the experience with
Real Madrid.

The forward will make his first ­appearance against United since leaving to join Real for a world record £80million in 2009, when the two sides clash in the Champions League.

United travel to Madrid for the first leg of their last-16 encounter on Wednesday night, when all eyes will be on Ronaldo.

The 28-year-old scored eight goals to help United win the 2007-08 Champions League, when they beat Chelsea in the final.

Ronaldo has since won a La Liga title with Real, but is desperate to get his hands on the Champions League trophy again.

Respect: Ronaldo has vowed not to celebrate if he scores against United (
Image:
Elisa Estrada)

Asked what it was like to win the Champions League with United, Ronaldo said: “It’s the ultimate. ­Winning the Champions League is when all ­feelings come together after an ­exhausting season of hard work — a lot of hard work with a lot of ­discipline.

“And having won a Champions League it’s something unique and I would like to repeat it here
with Real.

“It is great to be associated with a club like Real Madrid, the club that has won the most Champions Leagues. That’s a great motivation and honour. But the past is the past, and the present is more ­important.

“Real Madrid should have the ambition to win their 10th and that’s what we will try to do.

“I have to always  write my own history, ­independent from  where I play.

“Of course, titles are the most important thing and that’s what I have tried to do at the teams I’ve played for — leave my mark, give my contribution, so the club can win titles. That’s what I will continue to do in the next couple of years as well.”

Ronaldo scored in both games against old club Sporting Lisbon on the way to his Champions League triumph with United.

He did not celebrate either goal against Sporting and has reiterated his vow to show United the same level of respect if he is on target this week.

Struggling: Ronaldo has written off Real's chances in the league (
Image:
David Ramos)

“A player who has played a long time at a club, then goes to another team, if he scores, I think he shouldn’t celebrate,” said Ronaldo.

“For example, what I did when I was playing for Manchester, when we played against Sporting I scored, and I apologised to the fans.

“That’s a form of respect, but not the only one. There are a thousand and one ways of showing respect on the pitch. Only with respect can you achieve things.”

Real have struggled badly in La Liga and trail rivals ­Barcelona at the top of the table, but Ronaldo insists Jose ­Mourinho’s men are ready to show their best form in Europe.

“In the league we haven’t been doing so well, but the team has been doing better recently,” he said.

“We are still competing in the Champions League and Spanish Cup.

“We are a bit far behind the top teams in the league, but we still have a chance. Maybe it’s a bit less in the league, but we’re still in the two other competitions and we’ll keep on fighting to win.”

Meanwhile, Robin van Persie has put his Manchester United scoring streak down to piling on the pounds.

Best of the best: Fergie hails Ronaldo as Real's greatest ever player

BARCELONA, SPAIN - OCTOBER 07: Cristiano Ronaldo of Real Madrid CF (R) duels for the ball with Sergio Busquets of FC Barcelona during the La Liga match between FC Barcelona and Real Mdrid CF at Camp Nou on October 7, 2012 in Barcelona, Spain. (Photo by David Ramos/Getty Images) (
Image:
David Ramos)

Sir Alex Ferguson has hailed Cristiano Ronaldo as Real Madrid’s greatest player – and insists the Portuguese winger is at the Bernabeu for life, writes Simon Mullock.

The Manchester United boss believes the man he sold to Madrid for a world-record £80million in 2009 is better than greats like Alfredo Di Stefano, Ferenc Puskas and Zinedine Zidane (above).

And, although there have been reports that Ronaldo may quit Madrid for a return to Manchester with either United or City, Ferguson believes the 28-year-old is about to sign a new contract that will keep him out of the clutches of every other club in football. Ferguson said: “Real have had Galacticos, with players like Luis Figo, Zidane, Roberto Carlos and Raul, but I don’t think they have ever had anyone as good as Ronaldo.

“He has beaten all the records there. He’s beaten Di Stefano, Puskas and Hugo Sanchez.

“The boy is indelibly printed on the history of Real Madrid.

“I said when we sold him to Real that we should have asked for £150million – and we would have got it.

“Everyone talks about Ronaldo coming back, but I just don’t see it. He has got two-and-a-half years left on his contract and if you were to try and buy him back you are talking about hundreds of millions.

“That rules out everyone.”

Meanwhile, Ferguson has slammed the Premier League and Sky Sports for undermining Manchester United’s Treble bid