Lewis Hamilton said he is braced for a tough weekend after he finished a distant 11th in practice for the Hungarian Grand Prix.
As Charles Leclerc attempted to put his catastrophic crash in France behind him by racing to the top of the timesheets, Hamilton ended the day 1.1 seconds adrift of the Ferrari driver.
On an encouraging afternoon for McLaren, Britain’s Lando Norris took second with Ferrari’s Carlos Sainz third and world champion Max Verstappen fourth.
Mercedes secured their best result of a painful season at last weekend’s French Grand Prix, with Hamilton second and team-mate George Russell third.
But the silver cars were off the pace at a scorching hot Hungaroring – the venue for Formula One’s final race before the summer break – with both drivers complaining.
“How far off are we?” asked Hamilton, after completing his opening lap on the medium rubber.
“So, currently, P8, 1.9 sec to Leclerc in P1,” replied his race engineer, Peter Bonnington.
“1.9 to the same tyre?” was Hamilton’s disbelieving response.
Later, Hamilton called his machine “unstable” after he ran off the asphalt at Turn 4.
Hamilton has won a record eight times at the Hungaroring, but the British driver is facing an improbable task of adding to that tally considering Mercedes’ problems here.
“The car has been a bit of a struggle today,” he said. “It is crazy how it swings so much from track to track. But we have to try and figure out how we can get the car working.
“At the moment, it is a little bit loose and it is not doing what we want it to do so it has been a difficult day.
“Nothing has changed on the car since last week. I am the same driver this week as I was then, but for some reason, it is not working as well at this track.
“It is going to be a tough weekend, that is for sure, but we will give it everything and see what we have got.”
Russell, who finished in eighth, was equally frustrated.
He yelled: “What the hell is going on at Turn 1? I just can’t get round the first corner without locking up.”
Leclerc locked himself away in his Monaco apartment after the accident at Circuit Paul Ricard which leaves his championship hopes hanging by a thread.
The Monegasque heads into the 13th round of 22 with a 63-point deficit to Verstappen – the equivalent of two-and-a-half wins – but he will take some comfort from leading the way on Friday.
The surprise practice package was Norris in his McLaren. The British team introduced a radically revised car at the last round, and, after he qualified fifth and finished seventh in France, Norris delivered another strong display on Friday.
The 22-year-old finished just two tenths back from Leclerc, ahead of Sainz and Verstappen, with his team-mate Daniel Ricciardo fifth.
On the occasion of his 41st birthday, two-time world champion Fernando Alonso took sixth, one place ahead of Sebastian Vettel, who on Thursday announced he will be retiring from the sport at the end of the year.
After winning the Monaco Grand Prix in May, Sergio Perez has struggled for performance and the Mexican was half a second adrift of Red Bull team-mate Verstappen in ninth.
The Hungaroring, 16 miles north of Budapest, has bathed in 30-plus degree heat this week. But rain is expected to disrupt qualifying on Saturday afternoon, and there is the possibility of a jumbled grid for Sunday’s 70-lap Grand Prix.