Lewis Hamilton at a loss as Sebastian Vettel tops practice timesheets with fastest-ever lap around Monaco

Vettel became the first – and so far the only – man to drive a new-generation F1 car around the streets of Monte Carlo in fewer than 73 seconds

Lewis Hamilton couldn't keep up with the pace of Sebastian Vettel's Ferrari (Getty)

Sebastian Vettel was all smiles this afternoon when he became the first – and so far the only – man to drive a new-generation F1 car around the streets of Monte Carlo in fewer than 73 seconds. And the fact that he and Ferrari team-mate Kimi Raikkonen were first and third, and the Mercedes of the morning’s fastest man Lewis Hamilton and his team-mate Valtteri Bottas were only eighth and tenth was an indication that some things were awry in the second session of practice for the Monaco Grand Prix.

A red flag triggered after Canadian rookie Lance Stroll had crashed his Williams going into Casino Square as the one-hour mark neared, was in some measure a factor in Mercedes’ unhappy afternoon.

Up to that point Vettel had set the pace, first with a lap of 1m 12.759s, which displaced 2016 polesitter Daniel Ricciardo who had taken his Red Bull round in m 13.280s, then with 1m 12.720s.

Mercedes had elected to run the supersoft Pirelli tyres initially, as their rivals went for the faster ultrasofts. They had changed over just before the stoppage, and been unable to go faster, and when the session resumed there was so much traffic as others had gone in the opposite direction and were running on the supersofts in race simulations, that neither Hamilton nor Bottas got a chance to improve. It’s debatable, however, whether they could have even with that rarest of Monegasque occurrences – a clear track.

"I don't understand it,” Hamilton admitted, having been 0.196s faster than Vettel in the morning’s cooler conditions. As the ambient and track temperatures rose in the afternoon, it seems they stole some of the Mercedes’ grip.

"P1 was really good, the car was feeling great,” Hamilton continued. "Then there was a night and day difference, black and white, in P2. We couldn't work the tyres for some reason, there was a lot of sliding about.

"Now we have a lot of studying to do to find out where we went wrong, but I'm confident in my guys. I don't know if it's set-up. It's just with the tyres, I don't know why they weren't working.

“At least we have all day Friday for the engineers to look at the problem and come up with something. That gives them more time to work on the car, spread over two days, rather than having to do everything tonight.

“Monaco is always amazing to drive, but this is definitely the best car I've driven around here. Ferrari are very quick again and Red Bull are also looking good this weekend. We're looking forward to a real fight in qualifying on Saturday.”

“They’ll probably get it all figured out tomorrow, and give us the usual headache on Saturday afternoon,” a senior Ferrari engineer said with resignation. He was probably right.

Within Mercedes there is a strong feeling that changes made to the set-up for the afternoon had been responsible for creating the performance aberration.

“After a very positive morning session with both cars and drivers, the afternoon proved more difficult and we clearly took a step in the wrong direction with the car set-up over the break," Mercedes’ technical director James Allison said. "We’ll have a good think about it tomorrow in order to put things right."

Vettel topped the timesheets on the first day of practice in Monte Carlo (Getty)

As Jolyon Palmer suffered an engine failure on his Renault, there was good news for the third Englishman who will be racing this weekend. Jenson Button’s comeback performance vindicated his decision not to run in Bahrain, and he looked like he had never been away.

As team-mate Stoffel Vandoorne ended up 11^th with 1m 13.946s, Button recorded 1m 13.981s and was thus only 0.035s adrift on the same ultrasoft rubber. He never put a wheel wrong, and actually overtook the troubled Hamilton going into the chicane near the end of the 90 minutes.

“That was a hugely impressive performance,” the same Ferrari engineer observed with undisguised admiration. “He did a great job.”