Claus Bo Larsen claims he will not be influenced by Cristiano Ronaldo's reputation as a diver when he takes charge of the Champions League semi-final between Manchester United and Arsenal.

Ronaldo has been heavily criticised in recent seasons for going to ground too easily but the Danish referee believes the United winger will not cause any problems at Old Trafford.

"You have to give both teams a clean slate when refereeing," said the 43-year-old, who took charge of United's Super Cup defeat by Zenit St Petersburg in December. "I don't believe he will dive.

"I have seen him many times before and have warned him about diving in the past. I think you must be careful that you don't come in with certain ideas and make mistakes as a result. I'm looking forward to a fair game and will try to do my best."

Meanwhile, Nani has played down rumours of a bust-up with manager Sir Alex Ferguson after he was substituted at half-time during Saturday's 5-2 victory over Tottenham.

The 22-year-old, who denied claims he left the ground once he was taken off, said: "I accept why the manager substituted me and the team were better in every way in the second half but I was not responsible for the poor performance in the first half.

"I have no problem with the manager but I am still in my apprenticeship here."