Senna had achieved his first F1 race win with Lotus-Renault earlier in the year, in a soaking wet Portuguese GP.
The Belgian race should have taken place in June in scorching hot conditions but a new track surface broke up during the test sessions forcing the race’s postponement until later. The re-scheduled date was 15 September and conditions now were very different with the race starting under dark clouds and on a wet track surface.
Senna immediately bolted into the lead as Nigel Mansell stayed in touch in second position in his Williams-Honda. Then a slow pit stop for Senna to change onto slick tyres – a dry line was now starting to form on the track – and a better one for Mansell who had come in at the same time meant the Williams emerged from the pit lane in the lead right in front of the Lotus.
This is where Senna showed his extra genius in such perilous conditions. Exiting the pit lane and on the steep run downhill to the famous Eau Rouge/Raidillion section of the track, the Brazilian used every one of the 1000bhp or so on tap from his 1.5 V6 turbocharged EF15-spec Renault engine to blast past Mansell’s Honda-engine machine.
What made the move so breathtaking was Senna’s control of the car – he’d had to jink off the drying racing line and onto the still-damp part of the track to pull off the move. Consider this was just seconds after he’d left the pit lane so his slick racing tyres were still effectively stone cold and without any meaningful bite.
From there he was able to steadily pull away from Mansell to win by almost half a minute for the second of his eventual 41 wins during his F1 career.