BUDAPEST, Aug 6 - BMW Sauber's Robert Kubica was disqualified from the Hungarian Grand Prix on Sunday, handing Ferrari's Michael Schumacher a vital point despite his retirement three laps from the end.

The point awarded to the seven-times world champion for eighth place trimmed the overall lead of Renault's Fernando Alonso to 10 points with five races remaining and everything to play for.

Spaniard Alonso, the world champion, failed to finish after crashing out while leading.

Race stewards said in a statement that Kubica's BMW Sauber was found to have run two kilos too light. Poland's first Formula One driver, replacing Canadian Jacques Villeneuve, had finished seventh in his debut race.

Schumacher had been classified ninth in the provisional results, even though he did not finish, with all the other drivers at least three laps behind.

Brazilian team mate Felipe Massa moved up to seventh and the extra two points allowed Ferrari to reduce Renault's lead in the constructors' championship to seven points.

Stewards accepted that Kubica's car had not been deliberately underweight.

"The reason for the car being underweight was explained as being attributable to excessive and unexpected tyre wear (and therefore weight loss) arising through continued use of wet weather tyres in comparison to the accustomed and anticipated rate of wear for dry tyres," they said.

Kubica had completed the race on wet tyres after conditions had dried.

"The...tyres on Robert's car were in use for 51 laps and had sustained unexpected high rubber wear," confirmed BMW technical director Willy Rampf.

BMW accepted the stewards' decision.