Referee Steve Bennett sent off Man Utd's Cristiano Ronaldo last season

Referee Steve Bennett admits it will be a difficult task to spot incidents of diving in the FA Cup final.

Chelsea boss Jose Mourinho has already expressed his concern that diving could spoil the final.

Bennett said: "There are some very clever players who instigate contact and make it difficult for the referee.

"Sometimes there's contact but an exaggerated reaction to try to deceive the referee. It's nigh-on impossible to be sure. I hope we keep on top of it."

Mourinho stepped up the pressure on Bennett with his remarks about diving.

We shouldn't have contact with managers, but I respect them Referee Steve Bennett

He said: "I would be disappointed if some of the players were diving or trying to get others red-carded, I would be very disappointed with that."

Bennett, who is preparing for his first Cup final as a referee, has been involved in high-profile incidents with both Mourinho and Manchester United boss Sir Alex Ferguson.

In the 2005 Carling Cup final, the 46-year-old sent Mourinho to the stands after the Chelsea boss put his finger on his lips to Liverpool fans during their 3-2 victory.

And in January last year, he sent off Ronaldo after the Portuguese midfielder lunged at Andy Cole in United's 3-1 defeat to Manchester City.

But Ferguson hit out at Bennett for not giving enough protection to his players.

Bennett said history will not have a bearing on how he officiates Saturday's game - the first FA Cup final at the new Wembley.

"You move on," he said. "Sometimes players put you in positions where you have to react.

"That was a situation where Ronaldo launched himself through the air and the intentions were clear.

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"The laws of the game are clear and I have to apply them. When the boot is on the other foot, would they expect the opposite to happen if somebody did it to one of their players?