Sebastian Vettel has topped FP1 in Monaco, but the championship leader was made to work for it as the Ferrari of Fernando Alonso proved a potent threat late in the session.

Vettel went three tenths quicker with three minutes remaining, but as the chequered flag fell Alonso was on a fast lap – and managed to outdo the German’s time.

It didn’t last: Vettel too was on another quick lap, and returned to the top of the timesheets as he pumped in a 1.16.619, beating Alonso by a shade over a tenth. Both men looked confident in the aggression they showed behind the wheel, appearing particularly committed through the fast harbour section.

Nico Rosberg was a strong third for Mercedes with Felipe Massa – who is keen to make up for his troubled Spanish Grand Prix – a promising P4. The two McLarens of Hamilton and Button were next up, with Jenson just under two tenths shy of Lewis.

Monaco specialist Pastor Maldonado was a very impressive seventh – keep an eye on his progress this weekend – just beating the Force India of Adrian Sutil. The German racer – who has also proved himself a bit of a Monaco pro in previous visits to the principality – jumped to the front end of the times with under quarter of an hour left. Vitaly Petrov and Michael Schumacher completed the top ten.

Meanwhile, Mark Webber had a miserable session, a gearbox issue limiting him to three laps during FP1. However, the pace of the Red Bull means Webber will almost certainly be right amongst the frontrunners once he makes it on to the track.

Photo: Vladimir Rys/Getty Images

There were a number of incidents on the tight, twisty street circuit too. Jerome d’Ambrosio became the first man to use the run-off at the harbourside chicane, bypassing the kerbs early on; Heikki Kovalainen would take the first trip up the Ste Devote run off, whilst Tonio Liuzzi managed to crash on the approach to the chicane.

And it wasn’t just drivers from the lower-rung teams who had issues. Multiple Monaco winner Schumacher crashed with less than ten minutes remaining in the session, entering Ste Devote too quickly and swiping the barriers as he ran down the escape road.

The session also saw a stoppage at around the halfway stage, as the mysterious appearance of a puddle on the straight prompted the circuit directors to investigate. They dropped the red flag but restarted shortly after, the moisture seeming to be coming from an underground leak.