The really important part of his day came later. After leaving the circuit in his red Honda NSX sports car, Senna later hurried back, ostentatiously parking the car outside the motorhome of the Williams-Renault team. 'Talks took place.'
Earlier, there had been other talks. For most of the afternoon, the motorhome had been sealed off, closed to visitors. Within, Williams and his fellow director Patrick Head were in debate with Ron Dennis of McLaren, apparently deciding which team would have Senna in 1993, which Alain Prost.
To the Frenchman this may have come as a surprise, for he has had a deal with Williams-Renault for several months. On sabbatical this year, he is due, at Estoril on Tuesday, to have his first test in the car. Indeed, overalls and helmet in the colours of his new team are in the Williams motorhome, awaiting his arrival.
Will they ever be worn? Yesterday the paddock was rent with rumour, and it is getting to be like a cheap thriller, a 'whodrivesit'. This morning, rumour had it, there will be an announcement about the Williams No 1 for 1993. It will be either Prost or Senna - and whichever it is not will be the No 1 at McLaren.
Beyond any reasonable doubt, however, is that both teams will use Renault engines next year. With Honda's withdrawal at the end of the season, McLaren have been struggling to find a competitive engine for 1993, and few contemplated the possibility of Renault's stepping up to the plate.
'We look upon Williams as our partner,' Patrick Faure, the Renault Sport President, said earlier this year. 'We also supply engines to the Ligier team, yes, but Ligier is a customer. There is a difference.'
There is another difference, too. Where Williams is emphatically a frontline team, Ligier is not. Indeed, it is believed that the contract between Williams and Renault precludes Renault supplying engines to any other front- running team.
How, then, can McLaren - the most successful team of the last 10 years - have overcome this obstacle? Simple: by buying Ligier, either in part or in full. That, at least, is the suggestion in Portugal this weekend.
In this era of vaulting technological sophistication in Formula One, it is increasingly the car, rather than the driver, which does the winning. And while Formula One smugly clings to its image of relatively unfettered technology, the downside is that it is poor box office. If one team has a discernible performance advantage - as has Williams-Renault in 1992 - the race result is generally a foregone conclusion.
Two weeks ago, at Monza, Nigel Mansell announced his decision to leave Formula One for American Indycar racing, and one of the major crowd pleasers was gone. At the same time, the lingering threat of a temporary withdrawal by Ayrton Senna remained, and the possible simultaneous loss of two superstars has been contemplated with great concern by the powers-that- be in this sport.
Indeed, perhaps the Formula One world should now be viewed as a giant chess game, with most of the drivers pawns, and one or two - notably Senna - weightier pieces. Senna's philosophy is simple: if I can't win, I won't play. Until the last few days, it appeared, that meant he had to have a Williams for 1993.
Except that Prost, in there with a firm contract, refused to countenance Senna as a team-mate. How, then, to accommodate him? Well, perhaps, by organising Renault engines for McLaren, his team for the last five years.
If the reader is confused by these ridiculous goings-on, he is no more so than virtually everybody inside Formula One. One hesitates to use the word 'sport' at all in connection with this increasingly tawdry market place.
Emerson Fittipaldi, twice a world champion in the Seventies, is a visitor to Estoril this weekend. Now one of the stars of Indycar racing, he looked sadly about him yesterday: 'How many smiling faces do you see in Formula One now? In Indycar racing, all our fighting is on the track . . . .'
This afternoon Mansell is favourite to win his ninth grand prix of the season, after taking pole position yet again. Sadly, though, the race is almost incidental. Most of the action is in the motorhomes.
PORTUGESE GRAND PRIX (Estoril): Final qualifying times: 1 N Mansell (GB) Williams- Renault 1min 13.041sec (ave speed 214.40kph, 134mph); 2 R Patrese (It) Williams-Renault 1:13.672; 3 A Senna (Bra) McLaren-Honda 1:14.258; 4 G Berger (Aut) McLaren-Honda 1:15.068; 5 M Schumacher (Ger) Benetton-Ford 1:15.356; 6 M Brundle (GB) Benetton-Ford 1:16.048; 7 M Hakkinen (Fin) Lotus-Ford 1:16.173; 8 M Alboreto (It) Footwork-Mugen Honda 1:16.282; 9 J Herbert (GB) Lotus-Ford 1:16.628; 10 J Alesi (Fr) Ferrari 1:16.884; 11 T Boutsen (Bel) Ligier-Renault 1:16.930; 12 A De Cesaris (It) Tyrrell-Ilmor 1:17.240.Reuse content