With Perez ceding seventh to Button, the Briton closed on Alonso, while leaving his team-mate to fend off the attentions of Sutil and Jean-Eric Vergne, the Frenchman comfortably holding on to his place in the top ten. The anticipated gaps between the cars were not appearing, however, and radio messages began warning drivers that they may have to run further than planned before the race, in order to consider a one-stop strategy rather than two.
The game of cat-and-mouse continued beyond one-third distance, despite Jules Bianchi and Maldonado coming together – again without a safety car – until Felipe Massa suffered an identical accident to the one that ruled him out of qualifying, locking up and collecting the barrier with his left front corner as the track narrows into Ste Devote. The Brazilian was once again a passenger as the Ferrari skated into the run-off, before impacting the barrier at a slightly more acute angle than on its first attempt.
With a clean-up effort required, the safety car was finally summoned – its first appearance of the season – while the medical car also departed to turn one in order to transport Massa to the medical centre. The Brazilian had managed to extricate himself from the wreckage, but was fitted with a neck collar as a precaution.
The safety car's appearance also coincided with the leaders' 'new' pit-stop window. Raikkonen and Button had already become the first of the leading group to change tyres, with Alonso also getting in before his team-mate went off, while Perez and Jean-Eric Vergne took advantage of the interruption to pit as soon as the yellow flags appeared. Vettel and Sutil were next up, anticipating the safety car, but Rosberg and Hamilton were made to wait until the 'SC' boards were already established before they were summoned.
That suited the leader, but stacking the Silver Arrows appeared to work against his team-mate, who dropped to fourth by the time the order shook itself out, the two Red Bulls – having initially been picked up by Bernd Maylander – were freed in time to beat the Briton to Ste Devote.
The field remained at a controlled pace until lap 39 when Rosberg, undeterred by Vettel having shown him who was now behind, bolted away to lead by nearly a second at Casino Square. In his wake, Hamilton appeared most keen to make up places, twice looking at Webber into Tabac before then attempting to replicate a GP2 move at Rascasse. The Australian, although surprised by the latter move, ultimately had his rival covered on each occasion, and Hamilton was never quite close enough again.
Instead, the action switched to a little further back in a pack that remained closely bunched by an inability to generate temperature in the soft compound Pirellis. First, Button clipped the back of Alonso at Loews, unsettling his own momentum sufficiently for team-mate Perez to dive through at the chicane. The Mexican then tried to pull the same move on Alonso a couple of laps later, but only succeeded in forcing his adversary over the kerb as he avoiding a potential collision.
Whilst the recriminations continued as to whether the Ferrari driver ought to hand the place over for cutting the corner, a rather more serious incident brought a halt to proceedings. Max Chilton, recovering from his own moment at the chicane, allowed his Marussia to move over on the hapless Maldonado, sending the Venezuelan momentarily airborne before he speared into the wall at Tabac. Fortunately, the introduction of TecPro barriers at that point saved Maldonado from injury, but only served to envelop his car in a plastic cocoon, forcing the red flags as the second Marussia of Bianchi limped back to the pits, his front end collateral damage from the incident.
After allowing the field to change tyres – all bar Raikkonen and Nico Hulkenberg opted for scrubbed supersofts - and effect any necessary repairs on the grid, the race resumed behind the safety car before being unleashed on lap 48. Again, Rosberg got the jump on Vettel, pulling away from the two Red Bulls over the first flat-out lap. Alonso duly handed sixth spot to Perez, while Chilton picked up a drive-thru' for his part in the Maldonado accident.
Although Alonso tried hard to wrest sixth back from Perez, it was Sutil who was the first to gain a place amongst the top ten, surprising Button at Loews and making it through on the inside despite another kiss. The German then pulled an identical move on a sleeping Alonso to take seventh place before setting off after Perez.