World championship leader Sebastian Vettel secured his fifth pole position of the season after posting the fastest time in yesterday’s crash-marred qualifying session at the Monaco Grand Prix.

Vettel’s best lap time of 1 minute, 13.556 seconds gave Red Bull its sixth straight pole, ahead of McLaren’s Jenson Button and Vettel’s teammate Mark Webber.

“If you’d asked me before qualifying if I would have taken third, I probably would have,” Webber said.

Webber took pole at last week’s Spanish Grand Prix, Vettel took the previous four poles and already leads McLaren’s Lewis Hamilton overall by 41 points as he bids to win in Monaco for the first time.

It was a disappointing session for Ferrari’s Fernando Alonso, who was quickest in the final practice yesterday morning, but dropped to fourth in qualifying.

Mexican driver Sergio Perez crashed his Sauber exiting the tunnel near the end of qualifying.

Perez became the third driver to crash on Saturday, racing out of the tunnel and skidding across the track.

“It’s difficult to keep the focus and it’s difficult to keep the concentration when you don’t know what’s going on,” Vettel said. “We all wish him the best.”

Perez’s crash severely hampered Hamilton, as he had yet to set a lapped time and the heat went out of his tires as he waited nearly 40 minutes for qualifying to resume. The 2008 F1 champion will start today’s race down in seventh spot, a disappointment for the English driver, who was fastest in both the opening two qualifying sessions.

With Perez racing in the third session for the first time this season, the Mexican lost control of his car as he was about to come out of the tunnel. The front slid over to the right and slammed into the tunnel barrier, spinning the car round and sending it into a tire wall on the circuit.