How McLaren and Williams dropped down the order as the pendulum swung at Sepang

The competitive picture changed significantly between Melbourne and Sepang.

The two constants were Mercedes domination and a stronger than initially expected challenge from Red Bull. But falling off the board were McLaren and Williams, each of which had vied with Red Bull as best of the rest after Mercedes in Australia but were nowhere near the pace in Malaysia.

What had changed?

The respective demands of each track layout and how they impacted upon the traits of each car. Essentially the Albert Park track more greatly rewarded the horsepower and fuel efficiency of the Mercedes engine, whereas Sepang placed greater emphasis on aerodynamic performance.

Both qualities are always important of course but their relative importance varies track to track. The Mercedes W05 excels in both areas (to find out why, check out Sky F1's coverage this weekend from Bahrain), the Red Bull RB10 is aerodynamically superb but currently limited by its Renault engine. And the evidence suggests that both the Williams FW36 and McLaren MP4-29 currently lag aerodynamically.

The middle sector of the Sepang track mainly comprises fast, long-duration turns that punish any relative lack of downforce hard. If we look to the best times set through there in Sunday's race - taking the fastest time as 100% and relating the deficit of the others by percentage - we get the following picture:

1. Mercedes - 100%.
2. Red Bull - 100.31.
3. Ferrari - 101.44.
4. Williams - 102.55.
5. Toro Rosso - 102.78.
6. McLaren - 103.02.
7. Lotus - 103.16.
8. Force India - 104.05.
9. Sauber - 104.99.
10. Caterham - 105.47.
11. Marussia - 105.48.

There are a few caveats to those numbers. Force India, for example, had Nico Hulkenberg on a two-stop strategy so was on very old tyres when his fuel load was light, so we therefore never saw that car with the optimum combination of low weight and high grip. Fernando Alonso's numbers may be flattered in that he was on new options rather than new primes when his fuel load was lowest, as was Daniel Ricciardo.

If we take Sebastian Vettel's best rather than Ricciardo's - to give a like-for-like comparison with the Mercs - the Red Bull number increases to 100.83. But that's still puts the RB10 as a clear second-quickest. Williams' numbers may be unrepresentative in that Massa and Bottas were invariably stuck behind Button's McLaren - but their drivers still reckoned the FW36's main weak point around Sepang was its high-speed grip.

"We just don't have enough rear downforce," said Massa of a trait that will hurt the car a lot more here than in Australia. "Each time the circuit grip comes down, we fall back," he pointed out, "and that's a sign of lack of downforce."

"We are clearly lacking in downforce, particularly in the high-speed sections," conceded McLaren's Eric Boullier after the race. "We were focussed on reliability for these early races and so our development evolution is at a different phase to those of other teams. We actually gained aero performance here compared to Australia with our new nose. But because of the different circuit demands that still wasn't enough to prevent us falling back. We'd have fallen back further without the new nose.

"We have more performance going onto the car for Ba