Mercedes team chief Toto Wolff has been so tortured by his team's cars struggle for pace and performance this season that he has wanted 'to strangle' himself to end the agony.

The Austrian boss of the defending constructors' champions, who reeled off eight consecutive team titles between 2014 and last year, admitted his frustration after opening practice at the Emilia Romagna Grand Prix on Friday.

"Obviously, it is really painful while you are in the moment and certainly when I see our car pounding around five seconds off the pace you want to strangle yourself."

He said he was trying to take a positive attitude to the problem.

"But, as a matter of fact, I enjoy the challenge and I enjoy it being bad because, over the long run with these regulations, we're going to be good."

Wolff was reacting after seeing George Russell wind up 10th and Lewis Hamilton 18th in the rain-hit session at the Autodromo Enzo e Dino Ferrari where Ferrari's championship leader Charles Leclerc topped the times, five seconds faster than Russell.

Wolff revealed also that the violent 'porpoising' of the Mercedes cars had been so bad that they were not only 'undriveable' but were being damaged by bouncing effect.

"The feedback we're getting from Lewis and George is that there's literally zero grip,"he told Sky Sports. "This points to the tyres, but that is not the worst of it."

"We had George bouncing so much that he broke the stay on the floor – and you can't drive. You have to lift on the straight.

"I have never experienced in my life bouncing like this but clearly it's not driveable."

The 'stay' is a rod attached to the body and floor of the car to prevent the floor flexing downwards during 'porpoising' – a safety move introduced during pre-season testing when the new generation of cars were launched.

Despite the team's struggles to unlock the potential of their car, Mercedes believe they can fight back in the championship.

After three races, Ferrari lead with 104 points ahead of Mercedes on 65 and Red Bull on 55.

"I think when you're optimistic, and I'm rarely optimistic in my assessments, if we are able to unlock the potential in the car, I think we can fight for this championship," Wolff said.

"But, at the moment, when you see the gaps, particularly today, it seems a totally unrealistic endeavour, but we just keep continuing and trying to understand."

He added that it appeared on Friday that Ferrari had unlocked the performance in their car in the difficult conditions, but that everyone else was "all over the place" as they struggled to improve tyre temperatures and grip levels.