Cristiano Ronaldo was in treble form as Real Madrid tuned up for this weekend's Clasico with a stylish 4-1 win at Ajax to maintain their perfect start to the fledgling Champions League campaign.

Ronaldo, who had bagged the late winner in the Spanish champions' opening Group D win over Manchester City, was joined on the score-sheet by Karim Benzema, with Ajax's lone strike coming from Niklas Moisander.

"Real are back," said winning coach Jose Mourinho.

"This is the first time this season we've won three or four matches in a row, that's important for our objectives and our confidence.

"We have to keep going, We can't win everything, but when individual qualities translates into collective qualities it's normal that results follow."

Ajax coach Frank de Boer commented: "You can have respect (for Real) but you have to play your game. Today I think we had too much respect for them."

The scoreline would have been even more lopsided but for a series of fine saves by Ajax's goalkeeper, Kenneth Vermeer.

In front of a near-capacity 50,000 crowd, Madrid were quick out of the starting blocks, winning a series of corners in the first 10 minutes but failing to capitalise on their early dominance.

Ronaldo went close to putting the Spanish giants in front on the quarter-hour.

Pouncing on Kaka's pass, the Portuguese forward found himself clean through on goal and was only thwarted by Vermeer's quick thinking, the Ajax keeper charging off his line to produce a goal-saving block.

Vermeer proved his mettle again shortly after to deny attempts from Kaka -- given his first start of the season after coming off the bench in the 5-1 weekend La Liga rout over Deportivo La Coruna -- and Benzema.

Vermeer continued to keep the Spanish giants at bay until three minutes from the interval, when Benzema broke down the left side and cut the ball back for Ronaldo to prod home from close range.

It was due reward for Mourinho's men after no fewer than 14 first-half shots on Vermeer's goal, of which Ronaldo was responsible for six.

Ajax took to the pitch for the second half determined to avoid losing to Real in the group stage at home for the third consecutive season.

But their fate was all but sealed three minutes after the restart by an audacious overhead kick from Benzema.

It was the climax of a superb move begun by Marcelo, who found Kaka on the right, the Brazilian then floating in a lovely cross for Benzema to work his aerial magic by the far post.

Mourinho praised Benzema's contribution, saying: "He scored a fantastic goal. When he plays well, the team plays well, he's a great player."

Ajax reduced the deficit on 56 minutes when Christian Eriksen's corner was headed past Iker Casillas by Moisander to give the hosts some much needed hope.

Madrid then came under severe late pressure from Ajax, but Ronaldo put the game to bed, curling in a shot past Vermeer in the 79th minute, then two minutes later chipping in substitute Sami Khedira's pass over the hapless goalkeeper's head for his first ever treble in the competition.

Beaten Champions League semi-finalists in the past two seasons, Madrid now top the group by two points from Borussia Dortmund and will go into Sunday's clash against arch rivals and La Liga leaders Barcelona with a spring in their step.