Formula One champion Lewis Hamilton was quickest in both Hungarian Grand Prix practice sessions after Mexican Sergio Perez walked away unscathed from a spectacular rolling crash.
Hamilton, four-times a winner in Hungary and clear favourite for Monday morning's race, set a best time of one minute 23.949 seconds in the second session a 1.25.141 lap in the twice halted opening session.
Team-mate and title rival Nico Rosberg, 17 points behind after nine of 19 races, was second fastest in the first session but behind both the Red Bulls in the second at a track where he has yet to appear on the podium.
The first red flag came out in the opening session when Perez's wrecked Force India came to rest upside down on the track after what looked like a rear suspension failure pitched the car sideways into the barriers.
The shaken Mexican climbed out and walked away before being taken for checks at the medical centre.
The accident came only three days after most of the drivers had attended the funeral of Frenchman Jules Bianchi, who died last week in hospital of injuries sustained at the Japanese Grand Prix nine months ago.
The cars carried 'Ciao Jules' tributes to the 25-year-old, the first driver to die from race injuries since 1994.
"It was a really bad accident, pretty unlucky," Perez told reporters. "But everything's alright... we'll have to check everything in detail."
Force India decided to withdraw Nico Hulkenberg from the second session as a precautionary measure.
"The team will work hard to fully understand the cause of the failure and find a resolution in order to be ready for tomorrow's free practice," they said in a statement.
The session re-started after the Force India car was cleared away but was then halted with five minutes remaining when Kimi Raikkonen lost the front wing of his Ferrari and spread debris across the track.
Raikkonen, with his future at Ferrari in the spotlight amid speculation he will be replaced at the end of the year, was still third fastest in that session with Australian Daniel Ricciardo, last year's winner, fourth for Red Bull.
Ricciardo ended the day in a cloud of smoke, with his Renault engine blowing spectacularly to bring out the red flags again.
The team could be more optimistic about their performance, however, with Russian Daniil Kvyat second on the timesheets.
"If that was qualifying, we'd gladly take it," commented team principal Christian Horner.