Barrichello's 1min 15.487sec beat team-mate Michael Schumacher by 0.226sec after the Ferrari pair were the only men to set times on a dry track.

Heavy rain arrived 13 minutes into the one-hour session and made it impossible to better the times set by the Ferrari duo, who have dominated the season so far.

Montoya, whose Williams team-mate Ralf Schumacher is ruled out for three months after fracturing his back in a crash at the last race, was lucky to escape from a big accident mid-way through the session.

His car slid backwards into the gravel at turn six and was almost flipped as it flew into the barriers at high-speed. He did not complete another lap along with six other drivers.

Sauber's Felipe Massa, of Brazil, and Italian Giancarlo Fisichella did not set a time, as did Scot David Coulthard and Finn Kimi Raikkonen, who are both using McLaren-Mercedes' new car this weekend.

Spaniard Marc Gene, driving for Williams in place of the injured Ralf Schumacher, ended the session in third place almost four seconds slower than the Ferraris.

Jordan put in an unusually impressive performance with German test driver Timo Glock fourth quickest ahead of team-mates Giorgio Pantano, of Italy, and Nick Heidfeld, of Germany.

Minardi's race driver Gianmaria Bruni, of Italy, and Belgian test driver Bas Leinders were the only others within 10 seconds of the Ferrari drivers after going out early in the session.

BAR-Honda's British test driver Anthony Davidson spun at turn 13 as conditions worsened but ended in ninth place with Toyota's Brazilian Cristiano Da Matta completing the top-ten.