The FORMULA 1 GRAN PREMIO DE ESPANA SANTANDER 2012 was a perfect example of how a race can be won or lost on a fine margin and a good or bad strategy decision. Pastor Maldonado beat Fernando Alonso and won the race for Williams due to a good strategy call half the way through the race, while Lotus’ Kimi Raikkonen again had the car to win, but was a fraction off due to race strategy and conditions and he ended up third.

There were several key moments and decisions which decided the outcome of this race. The main one was the early second stop of Maldonado. But there was another before the race had even begun.

Lewis Hamilton should have won this race comfortably for McLaren, with a 0.6 second per lap car advantage. But a mistake by the McLaren team when he did his final run in qualifying ruined his chances.

Due to a refuelling error, Hamilton’s car did not have enough fuel in it to complete the lap and be legal at the end. Team boss Martin Whitmarsh has since admitted that he should have told Lewis Hamilton to abandon his hot lap, as the team had realised by then that it had not put enough fuel in his car. Had he done this Hamilton would have started the race from 6th place, with a time set earlier in Q3. Instead McLaren did not act, Hamilton completed the lap, switched the engine off and then the team tried to argue force majeur for the error. The FIA Stewards sent him to the back of the grid from where 8th was the best result achievable.

Hamilton made up four places at the start from 24th on the grid and managed to get his tyres to last 14 laps in the first stint, the longest of any front-runner. He had climbed to fourth place when he stopped and rejoined in 14th place. He made his way through the field with a combination of overtakes and a two stop strategy which meant he did 21 laps on his second set of tyres and 31 on the final set, both of which were the hard compound. He lost time in the second stint behind Massa, otherwise a better result might have been possible. He got ahead of Massa when the Brazilian served a drive-through penalty on lap 29 for using DRS in a yellow flag zone.

By extending the stints, Hamilton was able to make up places when the three stoppers made their final stop and he kept the tyres alive for 31 laps, losing only one place at the end to Vettel and almost getting one back from Rosberg. It was a fine drive, but he and McLaren know that his first win of the season was there for the taking this weekend, had they made a different decision in the heat of the moment in qualifying.

On Friday practice, with track temperatures above 40 degrees, the soft tyre was working well as a race tyre. However expectation before the weekend was that the temperatures would be lower on race day than the rest of the weekend.

This led some teams to plan to save three new sets of hard tyres for the race, as these have a lower working temperature range than the softs and would therefore come into their own in those conditions. This turned out to be the correct thing to do; the track was at 44 degrees on Saturday and this dropped to 32 degrees on Sunday and the hard was the faster tyre. Williams and Maldonado did this, Alonso scrubbed two sets of hards in 3rd practice and then used a set in Q1. This set would be the one he would use in the final stint. Red Bull were also one of the teams to save three sets.

However the plan didn’t quite work out for them as they didn’t have the pace in qualifying or the race. Sebastian Vettel was forced to use up all his soft tyres just to get through into the final part of qualifying. This meant that he had no new sets of softs for a run in Q3 and was only 8th on the grid. Both cars required a front wing change during the race, the team combined it with a tyre stop but it wasn’t ideal timing tactically. Vettel also had a drive through penalty, so he did well to finish ahead of the McLarens in 6th place.

The cars are so close together this year, the key to winning is about getting out the front of the pack early on, as Vettel did in Bahrain and Rosberg did in China.

This means that qualifying well is still important. Once again the race was fought out between the two cars on the front row of the grid.

Spain was only the second time in five races (the other was Malaysia) where the car leading the first lap did not go on to win the race. This was all down to strategy. Williams believed that they had a pace advantage over Ferrari and expected the challenge for the win to come from Lotus. However they knew they were vulnerable to Alonso’s excellent starts. Maldonado duly lost the start to the Ferrari driver and then Alonso had enough pace in the opening two stints of the race that Maldonado wasn’t able to get close enough to attack.

Importantly, however, the Williams had better tyre life at the end of the stints and at the end of the second stint, Maldonado closed up on Alonso, from over three seconds to half of that. Williams pitted him two laps before Alonso for the second stop and Ferrari allowed their driver to stay out and run into slower traffic. This is something they have allowed to happen before.

The call to try the undercut (pitting earlier than opponent and using pace of new tyres to get ahead when he stops) was made by Williams’ head of strategy Mark Barnett. He brought Maldonado in on lap 24 when he was 1.5 seconds behind Alonso. Having saved the sets of new hard tyres, Barnett calculated that he would then have the tyre life to do 42 laps with one more stop to make without losing pace at the end.

It was brilliantly executed; his in-lap was 0.4s faster than Alonso’s, the stop was only 0.2secs slower than Ferrari’s, but crucially on new hard tyres his out-lap was 2.6 seconds faster and the first flying lap was also a second faster. With Alonso losing time behind Pic, Maldonado had done enough to take the lead from the Ferrari when it stopped to laps later than the Williams.

However as Alonso pushed hard in his wake to stay with him in the final stint, we got a graphic example of how following another car speeds up the degradation of the tyres, Alonso wasn’t able to stay with Maldonado until the end, as the degradation caused by running in traffic was more severe than running in clear air. Alonso’s tyres had done three laps in qualifying, so were the same age more or less as Maldonado’s.

Although they had the fastest car in race practice simulations on Friday afternoon, were third and fourth on the grid and set the fastest lap of the race on Sunday by over a second, Lotus didn’t win. Why not?

Temperature has something to do with it; the drop to 32 degrees on race day took the edge off their speed (so fine are the margins now!). They also made a strategy mistake at the first stop, putting the cars onto a set of used soft tyres, rather than the hards. They pushed the stints out to make sure they’d have a chance at the end. As the temperatures rose towards the end of the race we got to see what the Lotus could do. The Lotus set the fastest lap of the race, over a second faster than the nearest car. Raikkonen's final stint was 18 laps, Alonso's 23 laps, Maldonado's 25 laps. Alonso was vulnerable to attack from Raikkonen in the final laps, but he ran out of laps. Perhaps if he'd stopped one lap earlier he would have passed Alonso at the end.

Starts are a vital part of race strategy and we saw the experience of Raikkonen over the nervousness of Grosjean at the start. Although the younger man was ahead on the grid, Raikkonen was ahead in the opening lap and Grosjean fell behind Rosberg, whose pace was much slower and so held him up. The Frenchman lost 8 seconds in the first 9 laps. Worse still, Mercedes pitted Rosberg first as a defensive move and he stayed ahead in the second stint, so Grosjean had to pass him on track.

The first win for Lotus this year is surely not far away.

The UBS Race Strategy Report is written by James Allen with input from F1 team strategists and from Pirelli.

Kindly provided by Williams F1 Team.

This is the Race History chart from the Spanish GP, kindly provided by Williams F1 Team. The chart's main use is to show track position and also gaps between cars. The zero line is best viewed as a "ghost" car which is setting the average lap time of the winner (his race time divided by 66 laps) and you can see how the lap times evolve relative to it. Note Lotus' pace relative to the leaders in the final stint, for example, when the temperatures went up and they set the fastest lap of the race.

The Zero line shows the winner’s average lap speed and the lines show the pace relative to that. The gaps for each car behind the leader are shown in individually coloured lines