Fernando Alonso scored a practice one-two ahead of Sunday's Monaco Grand Prix to at least offer hope Red Bull Racing can be conquered in qualifying.

Under clear blue skies and in warm sunshine, Ferrari star Alonso topped a tight three-way battle at the end of the first 90-minute session, narrowly pipping Sebastian Vettel and Robert Kubica.

For the afternoon run, light grey clouds eventually dominated and temperatures dropped by a few degrees, with light rain making an appearance towards the end - but Alonso remained the man to beat.

After setting a time of one minute 15.927 seconds for the most famous street circuit in the world that only covers two miles in P1, the 28-year-old Spaniard beat that by over a second in P2.

Running closer to qualifying trim and on light fuel, Alonso set a lap time of 1min 14.904secs, becoming only the second driver to lead the way this year in both of the opening sessions.

Again, though, he had close company, with Nico Rosberg looking to prove his form in Spain last weekend was an aberration, the Brackley-based Mercedes team driver finished 0.109secs adrift.

Red Bull's Vettel, who along with Lotus' Heikki Kovalainen ran for a session-high 47 laps, was 0.195secs down in third, suggesting a sixth successive pole of the season for the team may be in the offing.

Underlining Ferrari's improvement, Felipe Massa was fourth quickest - just two-tenths of a second off the pace.

Five-times winner of this event Michael Schumacher was also in close attendance, along with Renault's Robert Kubica, both less than three-tenths of a second behind Alonso.

As for the last two winners of this race around the principality, Lewis Hamilton and Jenson Button were seventh and ninth in the McLarens they have been hoping will push them close to taking the chequered flag again.

Hamilton was 0.345secs down, with Button more than doubling that as they sandwiched the Silverstone-built Force India of Adrian Sutil, with Mark Webber a surprisingly lowly tenth in his Red Bull.