Force India made an incredible jump to the front at this weekend's Belgian Grand Prix - but where did their stunning performance come from?
Earlier on in the season, when the team languished at the back of the grid, such pace seemed a dim hope yet Giancarlo Fisichella won pole position at Spa-Francorchamps on merit, he proved the pace of the car with the fastest low-fuel time in Q2 qualifying and he only failed to win because Raikkonen's perfect positioning at the post-safety car restart allowed him to use the KERS advantage to pass and stay ahead.
It was a baffling turnaround for Force India, but one that has its roots in a performance factor that has been there right from the start.
Force India have enjoyed excellent straight-line speed ever since the opening race of the season in Melbourne, where they set the fastest pace through the speed trap at Albert Park. In the 11 races before Spa, they were the fastest car through the speed traps in five qualifying sessions. It was even better in the races, with the fastest speed six times and their top car never clocking a speed lower than sixth.
The issue, however, was a lack of efficient aerodynamics. While they were fast on the straights, they were not fast enough through the corners. They were not developing enough low drag downforce (which mainly comes from the underfloor) and if they tried to add downforce through other means such as wing set-up, etc. the efficiency was not good and the increased drag made them much slower on the straights - with the trade-off making for an overall slower lap time.
From day one, the focus had to be put on creating the best diffuser solution to speed up the air underneath the car and also on developing the best solutions to steer away the 'dirty' turbulent flow from the front wing and allow clean air to enter the area under the floor.
Despite being a small outfit, Force India was in a good position to do this because, with a deal to run with McLaren running gear (effectively as a McLaren 'B'-team), they could focus their small design team much more closely on aerodynamic and chassis developments. They did this with regular upgrades - but it was not until Valencia that they finally found a big step in the level of efficient downforce needed to qualify and race at the front.
In Bahrain, they were the second team to bring in a double diffuser to join those who started the year with one. This improvement helped move them to within one per cent of the fastest Q1 time - but still saw them drop out at the first hurdle.
A new cascade wing, matched to the floor, arrived in Spain and Britain saw the next major set of upgrades, with another development to the wing that saw a new profile, cut-down endplates and an upper flap that mimicked the one on the Brawn.
There was another floor/diffuser development and alterations to the bargeboards and wheel spinner detail (both improving flow to the floor) as well as changes to the sidepods and upper bodywork.
While all these developments enabled them to retain pace relative to their competitors, none were big enough steps to move them forward and they remained consistently between 1 to 1.5 per cent slower than the fastest car in Q1 and only made it through to Q2 three times, with their best qualifying (in terms of per cent off the leader) coming in Germany, where they had introduced further alterations to the floor area at the rear of the tyres to work the new front wing.
Then came Valencia, where the major step was made, with modifications to the front wings, bargeboard area, the front of the floor and the sidepods. This upgrade, which worked to improve the performance of all the others, achieved what they had been desperately searching for - a low drag addition of downforce. It moved their fastest time to within 0.62 per cent of the top in Q1 and saw them come in just 0.770s slower than the top time in the low-fuel Q2. It was also the first race where one of their cars had run within a second of the fastest lap time.
Now they had a package that retained high top speed (they clocked the top fastest speeds in both qualifying and the race at Valencia) but also provided more efficient downforce - perhaps not enough to compete well at higher downforce tracks but enough to put them in the mix on medium and lower downforce circuits.
One race of experience with the new upgrade allowed the team to perfect the set-up for a circuit that suited their car very well, and another evolution of the front wing, with smaller upper flaps to balance the lower downforce rear wing, helped to perfect it for the season's first true medium downforce circuit.
Before the Valencia upgrade they always had the straight-line speed to fend off attack from behind but could never deliver a fast enough lap time in qualifying to get in front. Now, particularly at Spa's levels of downforce, they could get in front and have the grunt to stay there. Except, that is, when in a battle against KERS.
They have yet more wings of even lower downforce configuration coming, with an aerodynamic test ahead of Italy to make sure they work - and if they do, they should be able to prove they were no flash in the pan.