Hayden, fourth at Jerez, currently shares seventh place in the championship with class veteran Capirossi, who showed all his old fire and passion as he snatched a last-turn fifth at Jerez for Rizla Suzuki.
Anglo-American Hopkins showed he is recovering from his pre-season groin injury by also gaining a position in that last bend battle in Jerez, but his Kawasaki team-mate Anthony West is having a tough time with just three world championship points to show for his efforts.
Also desperately in need of a strong race of Sunday are Marco Melandri and Colin Edwards, who both have nine points to their credit from the 50 so far possible. Edwards has shown strong pace in both practice and qualifying, only for problems in the race, while Melandri is yet to get anywhere near his race-winning potential with the factory Ducati.
Spaniard Toni Elias returns to the scene of his greatest triumph, his one and only MotoGP victory in 2006. He is desperate for points after two tough opening rounds for his new Alice Ducati team. His team-mate Frenchman Sylvain Guintoli hopes to celebrate the birth of his second daughter with a points scoring ride on Sunday.
Finnish KTM star Mika Kallio took full advantage of the last lap crash of race leaders Alvaro Bautista and Marco Simoncelli to win the 250cc race in Jerez. Kallio is second in the championship. behind Italian Mattia Pasini who won on the Polaris World Aprilia in Qatar and finished second in Jerez to lead the way by four points.
Italian Simone Corsi took over the lead in the 125 cc World Championship after his win in Jerez. The championship is wide open after the crash of Qatar winner Sergio Gadea and mechanical retirement of his team-mate, world champion Gabor Talmacsi.
Estoril is never an easy weekend for teams and riders because of the weather. The wind from the nearby Atlantic Ocean can race through the hills surrounding the track, which includes the slowest bend in MotoGP, and which is bumpy in places.