Nico Rosberg took Mercedes' first victory of the season at an action-packed Monaco Grand Prix, which featured two safety car periods and a red flag.
Sebastian Vettel finished second but never really looked in contention for the win after he crossed the line 3.8s behind the flawless Rosberg. Mark Webber completed the podium in third after resisting sustained pressure from Lewis Hamilton during the race. Hamilton had been second at the start but lost out to the Red Bulls when he had to pit behind Rosberg during the first safety car period.
Adrian Sutil drove a well-measured race to take a fully-deserved fifth place, picking off Fernando Alonso and Jenson Button with overtaking moves at the Loews Hairpin along the way. Button finished sixth ahead of Alonso, Jean-Eric Vergne, Paul di Resta and Kimi Raikkonen in tenth, who had to make a late pit stop after contact with Sergio Perez and charged back into the points from 16th in the final ten laps.
After good starts, Rosberg and Hamilton managed to block off the Red Bulls into Ste Devote and then retained the lead for the opening stint. The main objective was tyre preservation, with lap times over eight seconds off the qualifying efforts of the top drivers.
Webber was the first of the front runners to pit on lap 26 from fourth, but Rosberg, Hamilton and Vettel continued to maintain a respectable pace at the front. They appeared to be targeting a stop after lap 30 but had their hands forced when Felipe Massa crashed heavily at Ste Devote and brought out a safety car.
It was a carbon copy of Massa's crash in FP3, with him locking up and hitting the wall on the outside of the track before hitting the wall at Ste Devote. While the car was cleared, Massa was seen sitting in a neck brace and the safety car period allowed the doctor to give him precautionary checks before he was taken to the medical centre.
Vettel and Red Bull reacted immediately, while Rosberg and Hamilton continued on. They had to pit on the next lap and Hamilton lost out as a result as he had to wait for Rosberg to be serviced first and rejoined in fourth behind the two Red Bulls.
At the restart Hamilton looked keen to make amends and even got the nose of his Mercedes up the inside of Webber into La Rascasse before the Red Bull got better traction on the exit and retained the position. Further back Perez was in a feisty mood and managed to re-pass Button at the Nouvelle Chicane after being told earlier in the race to let his McLaren team-mate through after skipping a corner. He also had an attempt at passing Alonso but could not make it stick as Alonso cut the corner.
The red flag came on lap 45 after a big crash for Pastor Maldonado. Max Chilton had lost out at the Nouvelle Chicane defending from Esteban Gutierrez, and as he rejoined he took to the inside of the track to defend from Maldonado. However, Chilton then moved back towards the braking zone approaching Tabac and the Williams was launched off the back of his Marussia, just landing before slamming in to the barriers.
Maldonado was quickly out of the car but the Tecpro barrier had been pulled right across the track and the race was red flagged. Chilton was given a drive through penalty for the incident and his team-mate Jules Bianchi also hit the wall in the aftermath before he retired at Ste Devote with a brake problem.
At the restart, Alonso yielded to Perez having cut the Nouvelle Chicane defending earlier, while Sutil passed Button in to Loews. Just a few laps later, Sutil repeated the trick on Alonso through the same corner as he showed impressive opportunism on the two world champions.
Rosberg eased away at the front while Hamilton put pressure on Webber, but a second safety car period occurred when Romain Grosjean ran in to the back of Daniel Ricciardo at the Nouvelle Chicane.
In the closing laps, Perez attacked Raikkonen coming out of the tunnel but was squeezed against the wall, damaging his car enough to have to retire with brake failure two laps later. Raikkonen had to pit with a puncture but managed to recover to snatch tenth place on the final lap, though he's under investigation for speeding behind the safety car.
It's not the only protest that is ongoing as Mercedes raced under a cloud when it emerged it had carried out a three day tyre test for Pirelli in Barcelona. Red Bull and Ferrari protested prior to the race, with all three teams and Pirelli summoned to see the stewards soon after the chequered flag.