MONTE CARLO, France, May 26- Sebastian Vettel set the fastest time during Thursday's opening free practice for Sunday's Monaco Grand Prix.

The 23-year-old Red Bull driver and defending drivers’ champion clocked a time of one minute 16.619 on his final lap of the session at the Monte Carlo street circuit, pipping Spaniard Fernando Alonso of Ferrari by one tenth of a second.

Alonso, who was fastest in opening practice at Monaco last year, looked to have beaten Vettel’s time but was held up by third-fastest German Nico Rosberg of Mercedes who was cruising back to the pits.

Brazilian Felipe Massa was fourth quickest in the second Ferrari ahead of Britons Lewis Hamilton and Jenson Button of McLaren, fifth and sixth fastest respectively.

Williams driver Venezuelan Pastor Maldonado was seventh fastest followed by German Adrian Sutil of Force India and Russian Vitaly Petrov of Renault.

Seven-time champion Michael Schumacher was tenth fastest in the second Mercedes, however the 42-year-old German finished the session on foot after crashing his car into the St devote wall at turn one in the final minutes of the session.

Red Bull driver Australian Mark Webber did not set a time and spent most of the session in the pits owing to a gearbox problem.