AP Sports Writer
MONACO (AP) -- Nico Rosberg kept his cool amid the chaos to win the crash-marred Monaco Grand Prix on Sunday and give Mercedes its first victory of the season.
The German driver began from the pole position for the third straight GP, but he had to re-start three times after the race was held up by a safety car, a red flag and the safety car again.
"Today the team gave me a great car and it's fantastic to see how we've managed to improve in a short space of time," Rosberg said after winning the race 20 years after his father won it. "Massive thanks to the team, we've really improved from Barcelona."
Rosberg finished ahead of championship leader Sebastian Vettel and his Red Bull teammate Mark Webber. Lewis Hamilton finished fourth after starting second.
"We shouldn't get too carried away," Rosberg said. "We still have a bit of an issue with race pace."
The red flag came out with about 30 laps to go when Williams driver Pastor Maldonado was nudged into the wall by Marussia's Max Chilton.
Earlier, Ferrari's Felipe Massa crashed and the safety car came out a second time when Frenchman Romain Grosjean smashed his Lotus into Daniel Ricciardo's Toro Rosso.
The 27-year-old Rosberg danced on the top of his car before jumping off to hug team members.
In 1983, the former world champion Keke Rosberg took the checkered flag in Formula One's showcase race.
"It's special, but honestly that's not what I was thinking of when I was crossing the finish line," Rosberg said. "It was such a special race, in the last races we had pole position but (dropped) back so much."
Rosberg won his other career GP from the pole in China last year and his previous best result this season was fourth in Malaysia, even though he started the last two from the front of the grid.
They were useful points for three-time defending champion Vettel, who extended his lead at the top of the standings to 21 points over Kimi Raikkonen and 29 over Fernando Alonso, who failed to repeat his Spanish GP win from two weeks ago and wound up seventh.
Raikkonen finished 10th after being barged by McLaren's Sergio Perez late on.
"Overall I'm very happy and pleased with the result," said Vettel, who started from third on the grid. "We know how difficult it is to overtake here."
Rosberg's driving was slick, but the crashes will dominate the headlines as Monaco again confirmed it is one of the most difficult tracks in F1.
Chilton lost control and moved across into Maldonado on his side, sending the Venezuelan off the wall and into the crash barriers. Chilton's teammate Jules Bianchi was dragged into the crash but no driver was hurt.
Massa, meanwhile, plowed into the wall and slid across the track in a carbon-copy of his crash in Saturday's third practice. He sat with his head in his hands and his neck in a brace as he received medical treatment a short time later.
It was eventful off the track, too.
A little more than one hour before the race, Red Bull launched an official protest against Mercedes.
Red Bull team principal Christian Horner demanded clarity as to why Mercedes was allowed to conduct in-season tire testing following the Spanish GP.
Rosberg refused to answer questions about the issue in the post-race press conference.
Early on, Frenchman Charles Pic's race ended when he had to bank his Caterham onto the side of the track and exit quickly as flames started shooting up from the rear right of the car. He was unhurt.
With fears over Pirelli's fast-degrading tires prominent in all five previous races this season, the overall pace was slower than usual.
"I was a bit surprised by the slow pace of the opening laps," Vettel said. "You expect to see two arrows in front of you, but you saw two boats going for a cruise."
Hamilton had just pitted for new tires on lap 30 when Massa crashed. As a result, when the safety car first came out, it affected Hamilton, who dropped behind Vettel and Webber and into fourth place when the race re-started.
"For us, we knew it was a little bit against us starting on the second row," Webber said. "It was nice to get Lewis."
It meant Rosberg no longer had Hamilton to protect him from Vettel, but he reacted well at the re-start.
"Very well done Nico, a fantastic job," Mercedes team principal Ross Brawn said. "With all the incidents going on, you judged it perfectly."