Alonso lasted until the end of lap 12 before needing to relieve himself of the shredded first set of soft option tyres, and the two Lotus double-stacked on pit road next time around. That left the still-to-stop Mark Webber minding the store on his medium tyres still five seconds ahead of Hamilton, with Button in third place still stubbornly resisting Vettel's advances, one of which resulted in slight front wing damage to the front wing of the RB9. To add to Red Bull driver's headaches, there was an issue with his KERS and he was also being warned by the pit wall to get out of the McLaren's dirty air in order to cool the car down. All the time, Grosjean was behind him just waiting for any opportunity to apply some DRS in order to pounce on one or both of them.
With Hamilton bearing down on him, Webber came in from the lead at the end of lap 23 for a new set of medium tyres, emerging in sixth place. That called time on all the cars that had started on a set of mediums and Button was due in next time around for his own change clearly struggling on the worn set - so much so that Vettel was able to jump ahead of the McLaren through turn 4 before Button could get back to pit road. Grosjean felt he could follow the German through, but he failed to leave enough space on he outside for Button and the two banged wheels in a heavy contact undoing all that good work by the Briton as Fernando Alonso was also able to stream past the pair while they sorted themselves out.
Button pitted next time around and reported no significant damage to his car - proving it by punching in some fastest laps once he resumed in eighth position, ironically immediately behind his sparring partner Grosjean who'd also been forced into a rapid second stop for a checkover and new tyre. The Frenchman was also under investigation by the race stewards for causing an avoidable collision, but before any word came down Grosjean pulled off a spectacular move around the outside of Felipe Massa up the hill into turn 4 to pick up sixth spot. Button fancied some of the same action and on lap 32 he pulled off a nice move of his own on the Ferrari at the chicane, with Massa clearly struggling for grip on worn tyres and forced to pit next time by for a fresh set.
This latest turn of events meant that Hamilton was enjoying an expectedly cushy 12 second lead over Vettel, with Alonso unable to pull up closer to Vettel than six seconds. But Hamilton was due for this own second stop of the afternoon, which dropped him down to fourth place slotting in behind Webber in third place; his fresh set of tyres made easy work of Webber, and after seeing this both Vettel and Alonso opted to bail into pit road before they could became the next target for the storming Mercedes.
Hamilton was back in the lead, while Vettel's latest stop had dropped him to sixth right behind Jenson Button for the second time today. Fortunately for Vettel, Button was in for his own stop at the end of lap 38 and Vettel then picked up an extra position when word came that Grosjean had indeed been handed a drive-thru penalty - not for the clash with Button which would be reviewed after the race, but rather for putting all four wheels off the track in his successful pass on Massa a few laps later.
Grosjean wasn't the only driver on the naughty step, with Nico Hülkenberg also handed a drive-thru for speeding on pit lane. He was the only Sauber driver left in the race by this stage, Esteban Guttiérrez having retired on lap 30 with a drivetrain issue. His was the second retirement of the day, after Adrian Sutil, had ended his 100th Grand Prix on lap 20 after a hydraulics leak on the Force India consigned him to the garage for the remainder of the afternoon. Valtteri Bottas was the next to exit on lap 45, pulling his smoking Williams off onto the grass verge at the exit of the final corner.
With 25 laps remaining, Lewis Hamilton was still in control of the race and Sebastian Vettel was 15s behind after a new round of pit stops for Mark Webber, Fernando Alonso and Kimi Raikkonen, while Jenson Button was in sixth still scrapping with the ever-feisty Grosjean, who finally put a nice and clean move on the McLaren with the help of a dab of DRS on lap 50.
That coincided with Hamilton's final pit stop, which put him back out on track side-by-side with Mark Webber for second place. Webber won the initial encounter but Hamilton quickly struck back at turn 3 which saw Webber fly clear off the side of the track in order to avoid a collision. The Red Bull quickly resumed, but the battle for second was now concluded.
Vettel handed over the lead when it came time for his final pit stop on lap 56, putting him over 10 seconds behind Hamilton when he resumed in third place immediately behind Raikkonen, who proved impervious to being passed despite being on significantly older rubber. Webber's final stop dropped him back into line just ten seconds off the back of his team mate in fourth, comfortably ahead of Fernando Alonso who was being harried by Romain Grosjean.
A dramatic retirement for Nico Rosberg on lap 65 with the back of his Mercedes ablaze with an engine oil fire would have been a sobering reminder to Lewis Hamilton that as good as things looked heading into the climax of the race, it could all change in an instant. The Mercedes pit wall redoubled their scrutiny of the telemetry from the race leader and upped their stream of advice to Hamilton over the team radio to help him micromanage his car's engine temperature to avert any similar