Ronaldo taunted on debut for Real

Real Madrid's record £80m signing Cristiano Ronaldo was constantly booed by some fans on his debut as the Spanish side beat Shamrock Rovers 1-0.

The winger left Manchester United to join Real this summer but had a bow to forget as he came off at half-time.

Ronaldo also suffered taunts of "who are ya?" when he sent a free-kick wide before Karim Benzema's late winner.

Meanwhile, Ronaldo's former boss at Old Trafford Alex Ferguson has not ruled out the player returning to the club.

The 24-year-old Portuguese international spent six seasons at United before switching to the Bernabeu.

"He may come back, you never know," said Ferguson. "Sometimes it happens that way."He loved United. If you look back at the six years he had with us, he never missed training.

"That's one of the things he has above all other players - he was never injured, he always played.

"And his best is yet to come. He is only 24."

Ronaldo has prospered under Ferguson's guardianship at United and was named Fifa World Player of the Year in 2008.

Brazilian forward Kaka, who has also been signed for £56m by Real Madrid, won that award in 2007, with Barcelona star Lionel Messi expected to win the 2009 gong.

There may be plenty of debate of which of the trio is the best player in the world but Ferguson has little doubt.

"Cristiano is a massive loss," conceded Ferguson, of a player who has scored 118 goals for United in 292 appearances.

"I have nothing but praise for the boy. He is easily the best player in the world.

"He is better than Kaka and better than Messi. He is streets ahead of them all.

"His contribution as a goal threat is unbelievable. His stats are incredible.

"Strikes at goal, attempts on goal, raids into the penalty box, headers. It is all there. Absolutely astounding."