Marquez edges Lorenzo in first practice

Marc Marquez edged out Jorge Lorenzo to set the pace in the first practice session of this weekend's MotoGP 2013 title decider at Valencia.

The two championship contenders were separated by just 18 hundredths of a second at the flag.

Marquez's Honda team-mate Dani Pedrosa completed an incredibly tight top three, finishing just six thousandths of a second down the road from Lorenzo.

Marquez can guarantee himself only the second rookie crown in premier class history by finishing fourth or higher on Sunday.

He therefore got his weekend off to the perfect start, running inside the top four for virtually the entire session before hitting the front with a 1m31.557s just one minute before the chequered flag flew.

That was just enough to shade Lorenzo, who had set the pace for much of the session and looked to have sealed top spot with a 1m31.575s set 15 minutes from the end.

Tech 3 Yamaha's Bradley Smith surged to fourth in the closing minutes, jumping ahead of factory stable-mate Valentino Rossi, who had enjoyed a spell at the top of the timesheets in the opening quarter of the session.

Alvaro Bautista got the better of Cal Crutchlow in the fight for sixth, with Stefan Bradl beating Ducati duo Nicky Hayden and Andrea Dovizioso to eighth. All five riders got within one second of Marquez's benchmark.

Hayden, whose 2006 showdown with Rossi is the only other occasion MotoGP's title has gone down to the wire in the last two decades, is making his final appearance for the factory Ducati squad this weekend.