The 2012 Chinese Grand Prix was all about tyre strategies with drivers choosing between two and three pit stops. After Schumacher's retirement on lap 13, Rosberg and Button were the only two drivers with a realistic chance of winning the race. While Rosberg chose a two pit stop strategy, Button opted for the aggressive three stop strategy.
Both drivers started the race on option tyres, however they chose different set of tyres in their first pitstop - Button who pitted on lap 11 chose options, while Rosberg who made his pitstop on lap 13 chose prime tyres.
Once everyone were done with their pit stops, Button was running in second place, four seconds behind race leader Nico Rosberg. Button made his second stop on lap 24 for a new set of medium tyres. He came out in 9th place and it took the British driver 8 laps to get back to second place. When Rosberg made his second and final stop on lap 34, he came out in 2nd place, 9.5 seconds behind Button. The German set some good laps as he decreased the lead by two seconds in next few laps.
Button lost more than 6 seconds on his final pit stop on lap 39 which put him in 5th place behind the trail of Massa, Raikkonen and Vettel. Had McLaren got the pit stop right, Button would have come 12-14 seconds behind Rosberg with tyres 5 laps newer than the German's. By the time Button regained second place, he was 25 seconds behind the race leader. He set some quick lap times in last 6 laps, gaining as much as a second as he closed the gap to just 20 seconds before the chequered flag was waved.
Considering the fact that Button gained as much as a second in last 6 laps, it would have been interesting to see whether Button could have won the race had McLaren got the pit stop right. The 32 year old would have got 16 laps to decrease a gap of 12-14 seconds with fresher tyres.
Despite teams pouring millions of dollars every year in pit stop practice, its becoming common now for pit crews to make such mistakes during the race.