Kimi Antonelli – the Italian teenager lined up to replace Lewis Hamilton at Mercedes next year – crashed out at 160mph only 10 minutes into his Formula One debut.

Antonelli, who turned 18 just five days ago, was thrust into Hamilton’s team-mate George Russell’s cockpit for the opening practice session of this weekend’s Italian Grand Prix at Monza.

But the home favourite lost control of his Mercedes at the high-speed Parabolica, sliding backwards through the gravel and into the tyre barrier.

“Are you OK?” Antonelli was asked over the radio. “Are you OK?”

He replied with an expletive before apologising to his team. “Kimi, all good,” assured team principal Toto Wolff. “All good, Kimi.”

Antonelli emerged from his damaged Mercedes before he was taken to the medical centre for precautionary checks. The crash registered at an eye-watering 45G.

Antonelli is expected to fill Ferrari-bound Hamilton’s seat in 2025. An announcement had been expected here at his home event.

Speaking on Thursday, Hamilton, 39, warned against putting too much pressure on Antonelli.

“I said a long time ago that I think that’s who the team should choose moving forwards,” said the seven-time world champion. “He’s one of those young, super-talented kids that’s come through, he’s a young adult now but he’s only 18.

“But it would be good for people to remember he is just turning 18. It’s an opportunity for him to grow. (At Mercedes) he would get to work with the best in class, learn from people that I’ve worked with for many years. It is a lot of weight on someone’s shoulders but, as I said, it’s a great environment and I think they will be able to nurture him and carry him through it.”

The session was red-flagged for 10 minutes before Max Verstappen put his Red Bull at the top of the timesheets.

The Dutchman is on a five-race winless streak, but he set the early pace at the Temple of Speed, lapping two tenths quicker than Ferrari’s Charles Leclerc.

Lando Norris, 70 points behind Verstappen in the championship following his triumph in the Netherlands last weekend, took third, 0.241 sec off the pace.

Hamilton finished seventh, half-a-second back. Second practice gets under way at 5pm local time (4pm BST).