Motor Racing: Senna belatedly agrees starting price: Championship leader's late entry for San Marino GP

AYRTON SENNA, the world championship leader, took the ongoing contractual negotations with his team, McLaren-Ford to the brink yesterday before deciding to compete in this weekend's San Marino Grand Prix. He left himself barely sufficient time to fly overnight from his home in Brazil and be at the Autodromo Enzo e Dino Ferrari for this morning's first practice.

Senna, still unable to reach an agreement for the full season, again committed himself to only one race. He is due to arrive in Rome at 7.30am, two hours before the start of the unofficial session. The first official qualifying session starts at one o'clock.

Money still appears to be a stumbling block between Senna and his team, and the Brazilian has also been lobbying for McLaren to be supplied with Ford's best available engines, which are currently Benetton's by contractual right. Before leaving Brazil on his 12-hour flight, he claimed Ford were ready to make the engines available. However, no one from Ford could confirm that and Benetton would still have to relent. What is clear is that Senna has played his political hand for another race, and that he prefers to be here to defend his 12-point advantage over Alain Prost.

Senna is also trying the patience of the authorities with his deliberations. Fisa, the sport's governing body, intends to block the present loophole which allows a driver to leave the sport in such uncertainty, race by race.

Senna has posed a distinct problem for Prost on the track. The Frenchman, firm favourite for the championship before the season started, could not compete with his old adversary at Donington Park 12 days ago, and was severely criticised. His explanations that his Williams-Renault had serious problems merely brought more scorn on him.

Prost said here last night: 'It seems that if I win it is because of the car, if I don't I am making excuses. The fact is that our car does have a problem in the wet. We hope to have it right in two or three races. I have no problem with the championship situation. We have had only three races, I am calm, and this circuit should suit our car and engine.'

It should, provided the sun continues to shine. The forecasters warn us to expect showers on Sunday, race day.