Lewis Hamilton got his Malaysian Grand Prix weekend off to the perfect start here yesterday, dominating both practice sessions in temperatures above 30C and very high humidity.
Having started from pole position yet only finished third in Australia, where McLaren team-mate Jenson Button won the race after making a better start, Hamilton has a point to prove.
"It's been a good day for me," he said. "We've made a few changes to the balance of the car since the last race and I'm much happier. But we'll still be making changes to improve our long-run pace, which can always be better."
Even though he was fastest, Hamilton had several off-track moments as he attempted to hone his car's handling balance as the day went on.
"I'm working as hard as I can to have as good a qualifying set-up as my race set-up and I think we've got a bit more of an understanding of how the car works on heavy fuel," he said.
"I went wide a couple of times on my long run in the second session, and looking after the tyres will be a tough call in the race, so it's all about finding the right balance. Around here, overtaking will be a little more possible than in Melbourne. Nevertheless, starting from the front will still be the best position for the race, and that's what I'll be going for tomorrow."
Button had a slightly less satisfactory day after losing time in the morning with an oil leak and then being pipped by two thousandths of a second by Mercedes's Michael Schumacher in the afternoon. Kimi Raikkonen will take a five place grid penalty for tomorrow's race, after Lotus had to replace his car's gearbox. F1 drivers are required to use one gearbox for five successive races, or face such a penalty.
"The morning was a little frustrating, but it didn't really matter as the track was still dirty," said Button. "In the afternoon I did some positive running on both tyre compounds and I think we have a good understanding of the tyre. But it's going to be tough on both compounds around here with all the humidity and the heat.
"I think the race will be tough for all of us; unless the circuit improves a great deal, there's going to be quite a few pit stops on Sunday."
McLaren believe their strongest opposition could come from Mercedes in qualifying, though Red Bull are likely to be stronger in race trim.
This race is not just hard on the cars or the tyres – the drivers suffer hugely, too. "It's the humidity more than anything else," Button explained. "For all of us this is one of the toughest races; I think most of us are used to training hard, so training for an hour and a half isn't an issue, but it's the humidity here that is tough for everyone. When you get onto the straight you can't breathe.
"The straights are normally a rest for us, when we just change gears and play around with a few switches. But here you don't get that luxury because you can't breathe. It's so hot, the air coming into the car, so it's very difficult. You've got to be very relaxed; if you're as relaxed as you can be it helps you a lot more in the race."
Formula One drivers are supremely fit athletes, but even the fittest can lose up to three kilos of bodyweight in an hour and a half race. "Some people [lose] even more," said Button. "It's quite a lot of fluid that you lose, that you sweat out of your body. I think everyone will be fine. The cars are a lot easier to drive than they used to be, in the race. In qualifying they're not, because they get quite lively, but in the race, because of the fuel load, they're easier.
"But here is still tough because of the heat. A lot of people do physical activity to get used to the humidity because it's such a shock. I feel sorry for Jean-Eric Vergne and a few of the others. They haven't been here before and it's a real shock walking outside. It hits you the moment you walk out of the airport."
To try to help, the drivers all had frozen drink bottles in the car, though they tend to warm up pretty quickly. The first man ever to try one, British star Tony Brooks in the French GP at Reims in 1959, recalls: "I had a bottle of orange juice because it was so hot. But the moment I took a swig of it during the race, it was like hot tea!"
In extremis, drivers wear water-cooled suits and skullcaps, as in Dallas in 1984, when the temperature reached 38C. Here the forecast limit is 33C, just about bearable without such kit.
Three things to watch in Sepang
Lewis versus Jenson
The victory in Australia was a major fillip for Jenson Button, and Lewis Hamilton was clearly not happy after finishing only third in the race after starting from pole position. Here he needs a strong result to keep his momentum and status, especially in a car that he knows can win races.
Button tips Lotus to do something spectacular here after their performance in pre-season testing and Romain Grosjean's third place on the grid in Melbourne. Their E20 is well balanced and good on its tyres, and it remains the dark horse.
How well drivers can conserve their tyres will be critical to success here. The heat and humidity take their toll on the rubber, as do the fast, sweeping curves of Sepang, where the left-hand tyres in particular take a real beating. The art lies in getting the best from the tyres without extracting their performance too quickly.
Sepang: Practice times
FIA Formula One Malaysian Grand Prix
1 L Hamilton (GB) McLaren-Mercedes, fastest lap time: 1min, 38.021sec, 19 laps completed; 2 S Vettel (Ger) Red Bull-Renault 1:38.535, 21; 3 N Rosberg (Ger) Mercedes GP 1:38.813, 21; 4 M Schumacher (Ger) Mercedes 1:38.826, 19; 5 R Grosjean (Fr) Lotus-Renault 1:38.919, 17; 6 M Webber (Aus) Red Bull 1:39.092, 20; 7 K Raikkonen (Fin) Lotus 1:39.128, 22; 8 P di Resta (GB) Force India-Mercedes 1:39.298, 23; 9 J Button (GB) McLaren 1:39.323, 15; 10 N Hulkenberg (Ger) Force India 1:39.440, 19; 11 V Bottas (Fin) Williams-Renault 1:39.724, 23; 12 P Maldonado (Ven) Williams 1:39.783, 23; 13 F Massa (Br) Ferrari 1:39.896, 16; 14 K Kobayashi (Japan) Sauber 1:39.910, 21; 15 F Alonso (Sp) Ferrari 1:39.980, 23; 16 J-E Vergne (Fr) Toro Rosso-Ferrari 1:40.099, 23; 17 H Kovalainen (Fin) Caterham-Renault 1:40.247, 19; 18 D Ricciardo (Aus) Toro Rosso 1:40.469, 23; 19 V Petrov (Rus) Caterham 1:40.857, 25; 20 S Perez (Mex) Sauber 1:41.085, 23; 21 T Glock (Ger) Marussia-Cosworth 1:43.170, 18; 22 C Pic (Fr) Marussia 1:44.580, 14; 23 N Karthikeyan (India) HRT-Cosworth 1:45.360, 8; 24 P de la Rosa (Sp) HRT 1:45.528, 18.
1 Hamilton 1min, 38.172sec, 28 laps completed; 2 Schumacher 1:38.533, 34; 3 Button 1:38.535, 30; 4 Rosberg 1:38.696, 34; 5 Ricciardo 1:38.853, 33; 6 Alonso 1:38.891, 27; 7 Webber 1:39.133, 29; 8 Vergne 1:39.297, 33; 9 Grosjean 1:39.311, 22; 10 Vettel 1:39.402, 25; 11 Maldonado 1:39.444, 35; 12 Hulkenberg 1:39.464, 26; 13 Di Resta 1:39.625, 20; 14 Kobayashi 1:39.687, 16; 15 Raikkonen 1:39.696, 29; 16 Massa 1:40.271, 28; 17 Senna 1:40.678, 34; 18 Perez 1:40.947, 33; 19 Petrov 1:41.464, 25; 20 Glock 1:41.681, 20; 21 Kovalainen 1:42.594, 19; 22 Pic 1:42.874, 24; 23 Karthikeyan 1:43.658, 18; 24 De la Rosa 1:43.823, 22.