The race remained static as the top runners conserved their tyres and the fact that the field remained very tightly bunched prompted most of the leading protagonists to switch from a planned two-stop to a one-stop strategy. Top ten runners Webber, Fernando Alonso, Kimi Räikkönen and Jenson Button had all made their stops when Ferrari's Felipe Massa had a massive accident at Sainte Devote, precipitating a safety car period. The Brazilian was shaken in the crash, which was very similar to one he had in practice on Saturday.
Vettel was changing tyres at the moment that the safety car was being deployed, but the two Mercedes drivers at the head of the field had to come in on the next tour. Although Rosberg was able to rejoin in the lead, Hamilton, who had to slow down on his in-lap to give the pit crew time to get ready after they'd dispatched the German, lost track position to both Vettel and Webber.
When the race resumed, Rosberg inched away from the Red Bull twins as Hamilton attacked Webber and behind them Räikkönen came under severe pressure from Alonso. But the Spaniard was caught napping by a feisty Perez, who had retaken seventh place from team-mate Button under braking for the chicane, and tried the same move on Alonso. The Ferrari man drove across the run-off area to retain sixth position, but was later told by officials to cede the position to his Mexican rival.
Then the red flag came out on lap 46 when Max Chilton and Pastor Maldonado tangled and the Venezuelan slammed into the barriers, before Chilton's team-mate Jules Bianchi got caught up in the aftermath. The cars reformed on the grid for the restart and were permitted to change tyres, alleviating concerns about tyre wear among the leaders.
When the race got going again, it took Rosberg little time to re-establish his lead over the chasing Red Bulls, while fourth-placed Hamilton complained off severe graining to his front tyres.
A driver on the move was Adrian Sutil, who pulled an opportunist move on Button at the hairpin for eighth place, then did the same to Alonso for seventh a few laps later. Alonso had picked up some debris on his front wing, which compromised his Ferrari's handling.
Another safety car period ensued when Romain Grosjean rear-ended Daniel Ricciardo on the run out of the tunnel down to the chicane on lap 63.
Rosberg yet again made a perfect restart and held his grip on the race, but there was more action further back. Perez's heroics into the chicane came to grief when he tried to squeeze his car into a rapidly closing gap between the barriers and Räikkönen, who had already committed to the corner in his Lotus.
Initially it seemed that both men had emerged unscathed from the incident, but near the end of the next lap, Räikkönen's rear tyre deflated. As he limped round and inadvertently held up the chasing pack, Button pulled a great opportunist pass on Alonso at La Rascasse.
Perez survived for an extra lap before worsening suspension damage forced him to pull off the circuit, elevating Sutil, Button and Alonso into fifth, sixth and seventh positions.
Jean-Eric Vergne completed an impressive weekend in eighth position for Toro Rosso, while a determined recovery from a disastrous qualifying netted Paul di Resta two points for ninth place. Having pitted to replace his deflated tyre, Räikkönen recovered to finish tenth.
Monaco Grand Prix, 26 May 2013
1 Nico Rosberg (Mercedes)
2 Sebastian Vettel (Red Bull)
3 Mark Webber (Red Bull)
4 Lewis Hamilton (Mercedes)
5 Adrian Sutil (Force India)
6 Jenson Button (McLaren)
7 Fernando Alonso (Ferrari)
8 Jean-Eric Vergne (Toro Rosso)
9 Paul di Resta (Force India)
10 Kimi Räikkönen (Lotus)