By Abhishek Takle

BUDAPEST (Reuters) - Nico Rosberg was fastest on the opening day of practice for Sunday's Hungarian Grand Prix after Mercedes team mate and title rival Lewis Hamilton crashed out.

World championship leader Rosberg, fresh from signing a two-year contract extension with the team, lapped the 4.3-km Hungaroring in one minute 20.435 seconds in the afternoon, after being second quickest in the morning.

"It's been a good start to the weekend and I think better than we expected," the German driver told reporters.

Hamilton, bidding to seize the championship lead for the first time this season, was fifth fastest after crashing with just four laps on the board.

The Briton, who was quickest in the morning, lost control of his Mercedes 15 minutes into the post-lunch session and skated across the run-off before clouting the barriers side-on.

"They've got new white kerbs here," said Hamilton. "I think I put my rear wheel slightly over the white line and touched the kerb."

He underwent a precautionary check at the medical center and appeared fine but his car had to be fully tested, ruling him out for the rest of the session.

The crash prompted a brief red-flag stoppage as marshals repaired the damage to the barriers in a session run in hot conditions with temperatures in the 40s.

ONE POINT GAP

Hamilton has won four of the last five races and trails Rosberg by one point overall.

He has triumphed four times at the Hungaroring, sharing the record for most wins at the track with Michael Schumacher.

"It's about getting in the swing of things and if you miss a session that's really what you miss," said Hamilton.

"When I get into the race it will be the first time really attacking and making those tires last as long as they need to go. But we've been doing it all year so there shouldn't be any excuses."

Former Hungarian winner Daniel Ricciardo, fifth in the morning, ended the day second fastest, half a second adrift of Rosberg.

His Red Bull outfit, the only team to beat Mercedes this year with Max Verstappen's win in Spain, are hoping to pose a genuine threat to their German rivals at a circuit that should suit their car.

Sebastian Vettel, who won the race last year, was third in his Ferrari ahead of fourth-placed Verstappen.

(Editing by Tony Jimenez)