McLaren chief Ron Dennis last night denied warning Formula One rookie Enrique Bernoldi he had the power to end his career as the Monaco Grand Prix ended in controversy.

Bernoldi said Dennis and Mercedes engine chief Norbert Haug had acted in an ''aggressive'' way towards him in a pit-lane confrontation after the Brazilian had held up their title-chasing driver David Coulthard in Monte Carlo.

The 22-year-old Arrows driver frustrated Coulthard for 35 laps of the 78-lap race as Coulthard attempted to force his way up the field after starting from the back of the grid when his car stalled at the formation lap.

Coulthard could only finish fifth as title rival Michael Schumacher scored his fifth and easiest victory in Monaco to extend his advantage to 12 points with 10 races left. ''Ron and Norbert came up to me in the pit lane,'' said Bernoldi. ''They were both very aggressive. They told me if you continue to drive in that sort of way again, you are not going to be in F1 for very long. I was very scared, they were very aggressive.''

Dennis insisted neither he nor Haug had issued any warning.

''That's rubbish. I said nothing of that sort,'' said Dennis of the claim. ''It was quite a while after the race when I talked to him and I was cool, calm, and collected and I was not angry. I just told him that in my opinion it was unsporting behaviour.

''Every time David made an attempt to overtake, he cut him off. You could argue its motor racing, but in fifteenth position it is different when you are hampering a driver who is clearly faster and has the world cham-pionship at stake.

Walkinshaw hit back at Dennis, saying: ''To say he will finish the career of a young driver in his first season in Formula One is outrageous.

''It is wholly inappropriate for people of that stature to verbally abuse a kid like that.''