Fernando Alonso blamed Ferrari's failure to maximise the potential of their car during Belgian Grand Prix qualifying on the wrong tyre strategy.

Alonso, who topped Friday practice but qualified in 10th, said Ferrari did not have enough fresh sets of soft tyres.

"In final qualifying I had one new set. We put it on at the end as we thought it was best but it rained," he said.

The changeable weather during qualifying meant the teams had to switch between intermediate tyres - meant for a damp track - and the harder and softer of the two types of dry-weather tyres at the will of Spa's skies during the three parts of qualifying.

Red Bull's Mark Webber set his pole-winning time of one minute 45.778 seconds during a window of drier conditions but Ferrari failed to anticipate the final flurry of rain.

Alonso set his fastest time - 1.663 seconds slower than Webber - in that same window but said that lap was set using the same tyres that he had used in the second part of qualifying as the team chose to gamble on the assumption that the track would stay dry enough for a final run on a fresh set.

"Everybody needed the same thing, one timed lap and then another timed lap," added Alonso.

"But they then had two new sets of soft tyres because they didn't use them in Q2 so that was the only thing.

Alonso is 20 points behind championship leader Webber but is still not counting himself out of the running in Spa, despite the disappointing result.

"The pace of the car is better so the aim for the race remains the same," said Alonso, whose best finish in Spa was second for Renault in 2005.

"We are fighting for the championship and so we must try and beat everybody, maybe win the race and maybe a podium.

Under the sport's regulations, each team is given 11 sets of dry-weather tyres to use throughout a race weekend - five soft (option) tyres and six hard (prime) tyres.