Formula One champion Lewis Hamilton posted the fastest time ahead of Mercedes teammate Nico Rosberg in a rain-hit second practice session at the Monaco Grand Prix on Thursday.

Early into the second session, the rain came thundering down and drenched the tight, sinewy track as spectators huddled for shelter.

Although the rain stopped with 30 minutes of the session left, teams were still in the garage with Rosberg walking around, arms folded, as he waited for the track to dry out enough.

Finally, with a few minutes remaining, drivers came back out for a few laps.

Hamilton, who was also quickest in the morning's first practice, clocked a leading time of 1 minute, 17.192 seconds - putting him 0.740 clear of Rosberg and 1.103 ahead of Ferrari's Sebatian Vettel.

Qualifying is on Saturday.

In the morning session, Hamilton posted the fastest time ahead of 17-year-old Max Verstappen, who impressed with a commanding drive on his first ever appearance on the notoriously tough Monaco track.

Hamilton, who has won three out of five races this season and signed a new three-year deal with Mercedes on Wednesday, was .149 seconds faster than Verstappen, who drives for Toro Rosso.

Verstappen, who is Dutch and touted as a future F1 star, impressed with his mix of aggressive driving and precision on a track where cars have to brake late due to the number of tight corners. His performance was even better considering the circuit was damp early on.

Daniel Ricciardo was third quickest for Red Bull, ahead of Vettel.

Rosberg, who is second behind Hamilton in the championship standings, had an early scare when he brushed his Mercedes against the barriers but did no damage. He was more than one second slower than Hamilton and posted the ninth best time in the morning.

Rosberg, who is German and grew up in Monaco, won last year's race from pole position after Hamilton accused him of deliberately undermining him in qualifying. Rosberg crashed under no pressure near the end of qualifying, forcing stewards to stop the session and denying Hamilton a chance to beat his time.

Rosberg won the Spanish GP two weeks ago to cut Hamilton's championship lead to 20 points. He is looking to become the first driver since Ayrton Senna to win the Monaco GP three times in a row.

Toro Rosso driver Carlos Sainz Jr. and Lotus driver Romain Grosjan also escaped without damage after spinning their cars.