ESTORIL, Portugal -- Italian world championship leader Valentino Rossi saw off a spirited Max Biaggi challenge to win the Portuguese Grand Prix for the third year in a row on Sunday.

The MotoGP champion Rossi piloted his Honda around 28 laps of the bumpy, twisting Estoril track near Lisbon in 46 minutes 48.005 seconds, 2.094 seconds ahead of compatriot Biaggi, also on a Honda.

Ducati's Loris Capirossi completed a podium sweep for Italy after prevailing in a spectacular last-lap battle with Spanish title contender Sete Gibernau, whose fourth place means he drops to 46 points behind Rossi in the championship race.

Biaggi made a flying start from second place on the grid, tearing away to take an early lead ahead of Rossi and Capirossi, who began in pole position on the 4.2-km track.

Careful cornering kept a narrow but stubborn lead for Biaggi in the first few laps, although Rossi was chasing hard on his heels and set one of several new unofficial lap records despite windy conditions.

Rossi, who won here on his way to claiming the world title in 2001 and 2002, finally overtook his arch-rival on the home straight at the halfway point of the race.

The 24-year-old Rossi then proceeded to build up a convincing lead with some dazzling riding, his front wheel often up lifting up as he powered down the straights and the RCV bike wobbling as he took daring lines on the tight bends.

"At the beginning Biaggi started very, very fast and had a very good lap time, so I decided to overtake Sete and Loris and try to follow him," Rossi said after celebrating his fifth victory of the season with a yellow-clad toy monkey.

"The speed stayed very high and after half the race I had two or three very good laps and it was possible to go away.

"I am very happy also because Gibernau finished fourth, so that's more points in the championship."

With five races remaining in the campaign, Rossi heads the championship tally with 237 points. Gibernau is second with 191 with Biaggi third on 161 and Capirossi fourth with 113.

Biaggi said he was glad to clear the first bend without incident after several riders had crashed out of the 125cc and 250cc races.

"I saw the lap time was pretty good and I knew only a few people can go this fast, so I tried to split the group and I could hear Rossi's bike, I knew he was close," said Biaggi, who won his one race this season when Rossi was given a time penalty after the British Grand Prix.

"After he passed me I could only do my best to stay close, but second is a good result as Sete was fourth. Things went well and I hope to win as soon as possible.

Capirossi, who set the fastest lap time of the day at one minute 38.412 seconds, found the pace at the start too quick even for the impressive Ducati four stroke.

"I tried to follow Valentino and Max, but it was so difficult, so I tried to overtake Sete," said Capirossi. "On the last corner I went on the outside and I overtook him just 20 metres from the line.

"I think the bike is getting better, but maybe not everything is perfect."