Monaco GP: Lewis Hamilton leads Mercedes 1-2 in FP1

The Mercedes duo traded places at the top of the timesheet before Hamilton asserted himself with the fastest time of the session roughly halfway through.

Rosberg was fastest of all in the first sector of the lap, but his later efforts to topple his team-mate fell short by less than half a tenth of a second.

Daniel Ricciardo interloped in this personal battle by briefly going fastest in the early part of the session, and he was one of only two other drivers to ultimately lap below 1m19s.

The Australian looked to have Red Bull's RB10 hooked up nice an early and he wound up third fastest, less than a quarter of a second slower than Hamilton.

The last man below 1m19s was Ferrari's Fernando Alonso, who leapt to fourth with 10 minutes left of the session to run.

That bumped world champion Sebastian Vettel to fifth. The German took a while to find his own groove and ended up half a second shy of his team-mate's best time.

Alonso's Ferrari team-mate Kimi Raikkonen also improved late on to round out the top six, less than a tenth clear of fellow Finn Valtteri Bottas in the best of the two Williams.

Sergio Perez had his Force India inside the top three early on, but although he improved his time the Mexican slipped back to eighth as the session wore on.

He was just under two tenths faster than team-mate Nico Hulkenberg, who complained of some braking issues and ended up just fractions of a second slower than Kevin Magnussen's McLaren.

Hulkenberg was the last man to lap below 1m20s in the session. His Force India rounded out the top 10, ahead of McLaren's Jenson Button and Esteban Gutierrez, who was an impressive 12th fastest for Sauber.

Lotus has shown improved form recently but struggled in this session, as Romain Grosjean and Pastor Maldonado could only manage the 13th and 14th fastest times.

Felipe Massa also struggled in the second Williams, winding up 16th fastest behind Jean-Eric Vergne's Toro Rosso.

There were suggestions ahead of the event that Monaco might present the toughest challenge of the season to the drivers, but there were only a handful of significant incidents.

Max Chilton's Marussia became stranded after an early spin at Mirabeau, while Adrian Sutil's Sauber struck the barrier after a spin at the same corner in the late-stages.

Raikkonen's Ferrari spun but continued at Ste Devote on his final run, while team-mate Alonso took to the escape road at Mirabeau after locking his brakes, but the Spaniard easily kept his car out of the barriers.

Pos Driver                Team                     Time      Gap      Laps
 1. Lewis Hamilton        Mercedes                 1m18.271s           32
 2. Nico Rosberg          Mercedes                 1m18.303s  +0.032s  31
 3. Daniel Ricciardo      Red Bull-Renault         1m18.506s  +0.235s  37
 4. Fernando Alonso       Ferrari                  1m18.930s  +0.659s  31
 5. Sebastian Vettel      Red Bull-Renault         1m19.043s  +0.772s  33
 6. Kimi Raikkonen        Ferrari                  1m19.467s  +1.196s  31
 7. Valtteri Bottas       Williams-Mercedes        1m19.494s  +1.223s  31
 8. Sergio Perez          Force India-Mercedes     1m19.666s  +1.395s  29
 9. Kevin Magnussen       McLaren-Mercedes         1m19.789s  +1.518s  29
10. Nico Hulkenberg       Force India-Mercedes     1m19.856s  +1.585s  38
11. Jenson Button         McLaren-Mercedes         1m20.033s  +1.762s  35
12. Esteban Gutierrez     Sauber-Ferrari           1m20.118s  +1.847s  33
13. Romain Grosjean       Lotus-Renault            1m20.207s  +1.936s  33
14. Pastor Maldonado      Lotus-Renault            1m20.241s  +1.970s  38
15. Jean-Eric Vergne      Toro Rosso-Renault       1m20.260s  +1.989s  36
16. Felipe Massa          Williams-Mercedes        1m20.517s  +2.246s  25
17. Adrian Sutil          Sauber-Ferrari           1m20.736s  +2.465s  18
18. Daniil Kvyat          Toro Rosso-Renault       1m20.914s  +2.643s  37
19. Jules Bianchi         Marussia-Ferrari         1m21.310s  +3.039s  27
20. Marcus Ericsson       Caterham-Renault         1m22.063s  +3.792s  40
21. Kamui Kobayashi       Caterham-Renault         1m22.492s  +4.221s  38
22. Max Chilton           Marussia-Ferrari         1m25.817s  +7.546s   7