Italian GP: Sebastian Vettel fastest in second practice after huge Marcus Ericsson crash
Ferrari's Sebastian Vettel set the pace in second practice at the Italian Grand Prix despite a high-speed spin.
The German, 17 points behind Mercedes' Lewis Hamilton in the championship, lost control at the famous Parabolica corner at the end of an impressive run.
Hamilton was third fastest, behind Ferrari's Kimi Raikkonen and 0.287 seconds slower than Vettel.
There was a huge accident for Sauber's Marcus Ericsson, who somersaulted several times at the first chicane.
His DRS overtaking aid did not shut as intended when the Swede hit the brakes. Ericsson was uninjured but the DRS continued to be an intermittent problem for his team-mate Charles Leclerc for the first part of the session.
Vettel was trying to get one more timed lap when he spun off, lightly tapping the wall.
Hamilton also made errors on his fastest laps, running slightly wide at the second chicane a couple of times, so the absolute pace of the Mercedes was not revealed.
"We did plenty of laps this afternoon in the dry and we could see that, like in Spa, we had a small gap to Ferrari on both the short and the long runs," said Hamilton.
"My laps felt pretty good, but Ferrari was a little bit quicker today. We're all working flat out right now in every part of the team, and we have work to do tonight as well - but there are some areas where we can see deficits, so I hope we can make a little step for qualifying.
"It has been a big battle for a number of races now, and they have had a small advantage since the middle of the summer, but we are pushing as hard as we can to overcome that."
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Form at the top
Vettel's advantage over Hamilton suggested that Mercedes are again on the back foot.
And the race simulation runs in the second part of the session strengthened that impression, with Vettel on average just under 0.2secs quicker than Hamilton on high fuel on the super-soft tyres on which most teams will start the race.
Vettel was out later than Hamilton because of the delay required to repair the light damage to his rear wing caused caused by his off at Parabolica.
If that form continues, Mercedes will be concerned, because they already expect to struggle at the next race in Singapore in two weeks' time.
"The car was working well today but I think we can still improve," said Vettel.
"I am not yet happy. The balance is not perfect yet but I think by tomorrow with more work the car will be fine."
On Friday, Hamilton was fighting a lone fight against the Ferraris - his team-mate Valtteri Bottas was nearly 0.7secs off the pace and just over 0.4secs off the Briton.
The Red Bulls are next best, but Max Verstappen in fifth was a second off the pace.