Preview - Portuguese Grand Prix.

Spaniard Sete Gibernau will be looking to pull back Valentino Rossi's 17 point championship lead at the last European clash before four long haul races, in the Portuguese Grand Prix at Estoril on Sunday.

Thousands of Spanish fans traditionally flood over the border to the Estoril circuit on the outskirts of Lisbon and have more reason than ever to swap their sofa for a grandstand seat at the Estoril circuit this weekend as Gibernau looks to repeat victory over Rossi in the last round in the Czech Republic.

Rossi's lead currently stands at 17 points over the Spaniard, with a maximum of 150 still up for grabs, and both riders will be looking to make the most of improvements made to their machinery in two days of tests which followed the Grand Prix at Brno last week.

Rossi's Yamaha team worked intensively to further develop the engine of his M1, which was also fitted with a new fairing exclusively for the test... but notably not the long awaited more powerful engine.

Meanwhile, Gibernau was able to experiment with the new exhaust system brought to Brno by Honda, which he declined to use in the race after adverse weather conditions had limited dry set-up time during practice. But will he choose to race with it this weekend?

The Doctor will be seeking four successive premier-class victories around the Estoril circuit this weekend, while Gibernau's record at the track, which is often buffeted by high winds, is not so good although he led until a few laps from the finish a couple of years ago when he crashed.

Third in the championship Max Biaggi has never won at Estoril, but finished second last year. Riding the Camel Honda, he trails Gibernau by nine points and desperately needs a win to boost his receding championship chances.

One man unlikely to be challenging the lead trio for his debut win this weekend is Honda rider Nicky Hayden, who faces a late fitness check after breaking his collarbone in a training accident in Italy on Saturday.

A confirmed absentee will be Shane Byrne, who continues his recovery from a dislocated wrist sustained at Brno. WCM regular Michel Fabrizio will take the British Superbike Champion's Aprilia ride this weekend, providing the 19-year-old Roman with a great chance to impress the factory teams.

American Colin Edwards was a disappointed man in Brno, finishing seventh on the Telefonica Movistar Honda. He was recovering from a virus and will be looking to at least repeat his second place at the British Grand Prix to consolidate his fourth place in the title chase.

Rio Grand Prix winner Makoto Tamada finished an impressive fourth in Brno to move into ninth place and the Camel Honda rider has a great chance to climb the table, only 17 points behind fourth placed Barros. The Repsol Honda rider fell from a podium position at Brno and is running out of time to turn his season around.

Meanwhile, Yamaha and Honda were not the only factories making progress at Brno, with their rivals Ducati, Suzuki, Kawasaki, Proton, WCM and Moriwaki all staying on for extra tests as the need to close down the gap to the lead riders becomes ever more apparent.

Italian Loris Capirossi started last year's race in pole, riding the Marlboro Ducati. His difficult season is improving and he was fifth in Brno and currently lies eighth in the Championship, seven points behind Carlos Checa. His team-mate Australian Troy Bayliss is fighting for his MotoGP future and needs some good results in the final six races of the year.

Suzuki's John Hopkins will also be out to impress: 'Hopper' was flying in Brno until sidelined with mechanical problems and the 21-year-old will surely arrive at Portugal with his confidence at an all time high.

The 250cc riders (lower pic) will be hoping for a dry tack for their 26 lap race after the problems they had in Brno. Spanish teenager Dani Pedrosa, the current 125cc World Champion, still leads the way despite finishing third in the Czech Republic behind Sebastian Porto and Randy De Puniet.

Pedrosa, riding the Telefonica Movistar Honda, still holds an impressive 30 point advantage over Frenchman De Puniet with Porto a further 13 points adrift in third place.

Spaniard Toni Elias won the race last year riding the Fortuna Honda and he heads a tremendous battle for fourth place with just six points separating him, Fonsi Nieto and Alex de Angelis, both who crashed out in Brno.

The 125cc race at Brno was one of the best ever and the 23 lap encounter on Sunday promises to be just as close with Italian teenager Andrea Dovizioso defending an impressive 36 points Championship lead.

Less than two tenths of one second separated the first four riders in Brno with yet another Spanish teenager Jorge Lorenzo beating Dovizioso, former World Champion Roberto Locatelli and Pablo Nieto to the line.

Locatelli in second place chases his third win of the season. Nieto secured his only grand prix victory at Estoril last year with Hector Barbara, who's third in the Championship, in second place.