Ruud van Nistelrooy's agent last night denied claims his client cheated the referee into dismissing Patrick Vieira during Sunday's draw at Old Trafford as it emerged the bitter spat between the two players had spilled over into the tunnel.

The pair were separated by team-mates almost half an hour after the final whistle with Vieira still incensed that he had been sent off by Steve Bennett for retaliating following a foul by the Dutchman 11 minutes from time.

Van Nistelrooy had leapt back and immediately looked at the referee despite no contact having been made.

Arsene Wenger and Vieira, who was shown a second yellow card for his reaction, subsequently accused the 27-year-old of "a form of cheating".

"But Ruud did not dive," insisted van Nistelrooy's agent Rodger Linse. He's not that sort of player and would never try to get anyone sent off.

"He did not do anything to lower himself to the level of those around him. He showed his intelligence and experience by refusing to get involved and just walking away from it all."

The FA will investigate claims that the pair had to be restrained from confronting each other after the game.

The Arsenal captain had waited to talk to the Dutchman at the end only for the striker to stride past him. Some 25 minutes later van Nistelrooy emerged from the home dressing-room willing to talk to his opponent, only for Vieira to refuse to speak to him and continue talking to Robert Pires and United's Eric Djemba-Djemba and Fabien Barthez.

"I'm not a cheat," said van Nistelrooy. "Really? So I touched you then, did I?" retorted Vieira, only for the United striker to sneer: "You have no class." That comment enraged Vieira to such an extent he had to be held back by colleagues as he shouted: "If you come any closer I'll smack you and put you down properly this time."