Williams technical director Sam Michal has admitted that the team considered it too great a risk to fit Bridgestone's intermediate tyres to early race leader Nico Rosberg's car when the rain began to fall at Sepang.
The German had made a blinding start from fourth on the grid to vault past the front row pairing of Jenson Button and Timo Glock, and continued to ease away at the front until making his first scheduled stop on lap 15. With the forecast rain yet to start, the #16 was sent back out on slicks, but was back for more suitable rubber just five laps later as the precipitation started. While not appearing that heavy, few teams took the option of fitting intermediates, preferring instead to go straight for the full wets in anticipation of a cloudburst.
"It was saying full rain was due around lap 20," Michael said of the team's weather information, "That obviously wasn't accurate because we had moderate rain for about 15 minutes before the full-on deluge arrived. Going to the intermediates [ on lap 22] would have worked better for us but, considering the radar pictures we had at the time, it would have been risky to have made that call."
While Rosberg dropped back following his second stop, Toyota took the gamble on Glock's car as the German followed Rosberg's pit-stop timetable exactly. Once on the more lightly-cut rubber, however, the Toyota began to scythe through the field, and was only denied second place by the stewards to count back to lap 31 after torrential rain forced the race to abandoned.
"The car was going really well and I showed my ability to consistently push on each lap and open the gap to those behind me," Rosberg reflected, "When the rain came, unfortunately the situation just didn't go our way."
Agreeing that the race should not have been restarted - and recommending a 4pm start for 2010 - Michael revealed that he had been pleased with the way both cars had performed across the weekend, and was unsurprised by Rosberg's return to the head of the free practice times on Friday and Saturday morning.
"We bought a new suspension component and a front wing endplate, and both performed as we expected," he disclosed, "We appear to be more competitive with a heavier fuel load than when we are running with less fuel, like in Q2, so Nico's lap in [qualifying] was good. We went a couple of laps shorter than normal to ensure a place on the second row [following the penalties to Barrichello and Vettel], but then his start was good - although you could probably put it down to some great engine torque from Toyota.
"For most of practice, Kazuki [Nakajima] was very close to Nico but, when the grip ramps up like it did in qualifying, Nico seemed able to extract just a little bit more out of the car. Tyre wear wasn't a problem, but Kazuki lost out to various KERS cars at the start, and we need to see the system on FW31 as soon as possible."