Budapest: World championship leader Nico Rosberg celebrated signing a new two-year contract with Mercedes by topping the times after Lewis Hamilton had crashed during Friday`s free practice for Sunday`s Hungarian Grand Prix.
The 31-year-old German seized his chance and took full advantage after his team-mate and defending three-time champion Hamilton hit the barriers only 13 minutes into the second practice.
Hamilton was unhurt, but after returning to the pits in his car he took no further part in the 90-minute session.
The car was stripped down for repairs and, after a visit to the medical centre, Hamilton was left as a spectator.
"Obviously, it`s a great feeling to start the day like that with the contract being sorted," said Rosberg, who is to stay with Mercedes until 2018. "That was always going to be a positive boost."
Hamilton said: "My apologies to the crew for all the hard work they have ahead and getting it back together. Fortunately I got a good feel for it in the few laps that I had and the pace is clearly there."
He added that he remained confident of bouncing back on Saturday to claim pole position on one of his favourite circuits, where on Sunday he hopes to grab a record fifth win.
"I hope I can make up the time lost in tomorrow morning`s practice session and come back strongly in qualifying, but obviously, not the greatest session for me today."
Rosberg clocked a best lap in one minute and 20.435 seconds to wind up half a second faster than nearest rival Australian Daniel Ricciardo of Red Bull and nine-tenths clear of third-placed four-time champion Sebastian Vettel of Ferrari.
He added: "It was an impressive day for us, performance-wise, but doesn`t necessarily mean we`ll be in quite such a strong position tomorrow, but for now it`s very positive.
"I`m feeling great out there and the car is very quick, so it was a good start to the weekend.
"We got everything done in terms of qualifying and race simulation work and it`s all looking very good. I think the new surface suits us, so I`m optimistic."
Dutch teenager Max Verstappen was fourth fastest in the second Red Bull and Hamilton fifth, even though he did not run on the super-soft tyres during his brief 14 minutes on track at the start of the 90-minute session.
The defending three-time champion lost control of the back end of his car out of Turn 11 on the tight and twisty track and hit the barriers side-on.
He was able to re-start and drive gingerly back to the pits, but after an inspection the team decided to strip his car down.
Kimi Raikkonen was sixth for Ferrari ahead of two-time champion Fernando Alonso of Ferrari and his McLaren Honda team-mate 2009 champion Jenson Button.
Nico Hulkenberg was ninth ahead of his Force India team-mate Sergio Perez.
Ricciardo, who won in Hungary in 2014, said he felt that his Red Bull team were battling Ferrari for second behind the Mercedes.
"If we`re close on Friday, it doesn`t change too much on Saturday," he said.
"I would say today`s probably quite representative for now."
Red Bull has closed to within six points of second-placed Ferrari in the constructors` championship and Ricciardo said he hoped that they could make further progress this weekend.
"We`d like to be a bit closer to Mercedes, but at the moment we`re within reach of Ferrari," he said. "It`s going to be a good battle and I`m looking forward to that."
Vettel, who has struggled for consistency with Ferrari and suffered successive gearbox problems, said: "I`m not entirely happy with the balance, but I think we can improve overnight.
"It`s not a surprise that Mercedes is good. It`s quite obvious that Mercedes was very competitive in the morning and afternoon.
"I haven`t seen the long runs, but as I said, we need to work on ourselves and then see where we are."