The UBS Race Strategy Briefing is prepared by JA on F1, with input and data from several F1 teams.

This was a great win for Jenson Button, with Sebastian Vettel using race strategy and a piece of fortunate timing with the safety car to steal second place away from Lewis Hamilton.

For the second consecutive year Sauber’s Sergio Perez was a trailblazer, covering the race with just one stop and his performance on the medium tyre in the first stint changed the thinking of many of the top teams about how to approach the race.

As the first race of the season the Australian Grand Prix is always something of a test case for how race strategies have been affected by new generation of tyres and rule changes, such as the one banning the exhaust blown diffuser.

This weekend we saw clearly that the 2012 Pirellis are more suitable race tyres for F1 than last year’s; they allow the drivers to push a bit more and they wear differently from the 2011 versions, which would wear quickly along the shoulder, whereas the 2012 models wear evenly across the tyre, which is positive and makes them slightly more predictable. But performance still drops sharply if you stay on them too long.

The expectation going into the race was that the leading drivers would do a two stop race, starting on used soft tyres, taking a second set of used softs at the first stop around lap 19 and then pitting for medium tyres around lap 39.

McLaren controlled the race from the front row of the grid and the victory was only threatened 22 laps before the end, when the safety car neutralized the field and removed Button’s lead, with Vettel right behind him. Lewis Hamilton didn’t have the pace to stay with Button and some bad luck with strategy cost him second place.

The start was the decisive moment. Hamilton had qualified on pole, but Button had gained the strategic advantage over his team mate by winning the start, which meant that he had first call on when to pit.

He made his first stop on lap 16 and moved onto the medium tyre. This meant Hamilton had to come in a lap later. Hamilton’s tyres were already going off significantly and he lost 3.4 seconds on lap 16 and on his in-lap to the pits on lap 17. He lost a further 1.4 seconds on his out lap. Worse still, he rejoined behind Raikkonen and Perez, who was on the medium tyre and one-stopping. By the time he passed Perez he was 11 seconds behind Button. More significantly, Vettel had gained seven seconds on him through this period. The world champion also stopped at the ideal moment - lap 16 - before the tyre performance dropped off and was now just two seconds behind Hamilton. This time lost for Hamilton would prove decisive at the second stops. Vettel had opted for the soft tyre, while Hamilton and Button were on medium.

With an 11 second gap between Button and Hamilton at the end of the second stint and the tyres going off on both cars, the McLaren team decided to pit both of their cars at the same time, on lap 36. Their in laps were identical, but Hamilton’s out lap was 3 seconds slower than Button’s, meaning he was vulnerable to Vettel.

People have questioned the wisdom of pitting the two cars on the same lap and it’s something that McLaren have been working on, as it’s hard to achieve and requires a very well drilled pit crew, to have the second set of tyres ready to go. Being able to double stop has significant strategic advantages in multi-stop races, where an extra lap on fading tyres can cost a lot of time. But in a two stop race, it was an interesting decision to try it.

The Red Bull team had seen McLaren stopping, but left Vettel out as he was lapping faster than the McLarens at that point.

So he was on target to jump Hamilton at the second stops anyway, but it was guaranteed when the safety car was deployed as Petrov’s car had broken down on the pit straight.

Vettel dived into the pits from the lead and rejoined in between the McLarens, ahead of Hamilton. From 6th on the grid after a disappointing qualifying session, Vettel had made the most out of the opportunity presented to him by McLaren and Hamilton.

The total time needed for a pit stop at Albert Park is 25 seconds, which is one of the longest of the year. This is because the pit lane is long and the speed limit is just 60km/h, rather than the usual 100km/h, for safety reasons. This encourages drivers to do less stops rather than more. Even though Raikkonen, for example, had three sets of new soft tyres at his disposal, he didn’t go for a three stop sprint strategy because of the time that would be lost in the pits.

So from outside the top ten there were always going to be a few cars that would start on the medium tyre and try to get to lap 28 or 29, then switch to the soft. The front runners would never have planned to do this as simulations showed it to be 20 seconds slower than a 2 stop if you can run in clear air.

Last year Sergio Perez did a one stop race and finished seventh (although he was later disqualified for rear wing irregularities). It was assumed that several drivers would try this. In the event only three started on the medium tyre: Perez, Vergne and Petrov. Vergne did a two stopper, but Perez managed to go from 22nd on the grid to finish 8th. More importantly his pace around the time of the leaders’ first pit stops showed that the medium tyre as not only more durable than the soft, but was fast too.

Going into the race the strategists knew that on one single qualifying lap the soft tyre had been 0.8secs faster than the medium. But they believed that in the race that gap would be smaller, probably around 0.5 seconds. If you had a new set of options - as Raikkonen did for example – that was a faster choice than a new set of mediums. But the gap between the two tyres turned out to be so close that if you only had used softs, as all the front runners had, then a new set of mediums was better for most.

With the leaders forced to stop as early as lap 16, Perez was lapping comfortably in the 1m 33s which convinced several strategists that the medium was the best tyre to be on that day. Webber went to it first, followed by Button, Hamilton and Alonso. Vettel, Raikkonen and Kobayashi went for soft. The Japanese driver then underlined Sauber’s gentle action on the tyres by extending his middle stint on softs to 23 laps; longer than Alonso managed on new mediums in the Ferrari !

Perez’ strategy saw him rise to second place by lap 20 before the tyre started to really go off – he dropped five places and ten seconds in three laps as the cars that had pitted for new tyres overtook him. But he made his only stop on lap 24 and drove to the flag on a set of new options. He was racing Maldonado, Rosberg, Kobayashi and Raikkonen and finished 8th, having started at the back of the grid. The Sauber’s ability to run long stints on the tyres will bring them plenty of points this year.

The UBS Race Strategy Report is written by James Allen with input and data from strategists from several teams.

The winner’s average lap speed is shown as the zero line.