Gibernau was third fastest in Friday's practice session

Sete Gibernau, who was third fastest in practice, leads the way after a lap of one minute 48.969 secs, 0.089 seconds faster than team-mate Loris Capirossi.

Rossi looked on course to pip them for pole but hit problems on the final corner and had to settle for third.

Championship leader Nicky Hayden is fourth with James Ellison in 17th spot.

Defending champion Rossi lies eighth in this year's standings, and this is his first front-row place of a troubled season.

Hayden is four points ahead of Capirossi and Honda's Marco Melandri, who finished sixth fastest behind Shinya Nakano.

Gibernau, who has twice been championship runner-up but has yet to make the podium this season, was understandably satisfied with his ride.

"It's only the qualifying session, but for me it feels like a little victory," he said.

"The bike's going very well here and we managed to put in a pretty fast lap."

Rossi, who has won at Mugello for the last four years, was also satisfied with his day's work.

"We have been off the front row of the grid for too long. We have made life hard for ourselves," he said the 27-year-old.

"Everything went well. I was close to the Ducatis and even though I lose a little bit of ground to them on the final curve each lap I think we can do well tomorrow."

MotoGP qualifying (Sat):

1 S Gibernau (Sp) Ducati 1:48.969
2 L Capirossi (It) Ducati 1:49.058
3 V Rossi (It) Yamaha 1:49.167
4. N Hayden (US) Honda 1:49.212
5 S Nakano (Jpn) Kawasaki 1:49.328
6. M Melandri (It) Honda 1:49.343
7 J Hopkins (US) Suzuki 1:49.478
8 D Pedrosa (Sp) Honda 1:49.516
9 C Stoner (Aus) Honda 1:49.915
10 M Tamada (Jpn) Honda 1:50.084

250cc qualifying (Sat):

1 J Lorenzo (Sp) Aprilia 1:53.787
2 Y Takahashi (Jpn) Honda 1:54.174
3 R Locatelli (It) Aprilia 1:54.309

125cc qualifying (Sat):

1 L Pesek (Czech Rep) Derbi 1:58.202
2 M Pasini (It) Aprilia 1:58.335
3 H Faubel (Sp) Aprilia 1:58.851