Valentino Rossi came close to completing a perfect start to his Yamaha MotoGP comeback as he led most of Thursday night's practice for the Qatar season-opener.

Riding an M1 at Losail for the first time since 2010, Rossi went top of the timesheets on his opening flying lap. That set the tone for much of the session, with the seven time champion staying ahead of the pack and only briefly deposed by team-mate Lorenzo.

Tech 3 Yamaha's Cal Crutchlow and reigning double champion Lorenzo were both able to edge under Rossi's best in the closing minutes. But the Italian - who used a single set of tyres throughout - was pleased with his performance as he finished just 0.071s from fastest man Lorenzo.

"It is a great start for us," said Rossi. "We confirmed the different setting from Jerez, the bike was good from the beginning and I could stay in first for a long time.

"Our lap time was OK, especially given the condition of the track and because I used just one set of tyres to understand if I could be fast with a lot of laps.

"The setting and balance of the bike is good so it looks like we can be competitive... We are already strong."

Rossi sought a return to Yamaha after suffering the worst results of his career during two winless seasons with Ducati.

The Doctor starts this season having led just one of the nine days of official winter testing and having stated that he must 'raise his level' to reach Lorenzo and Dani Pedrosa.

But 2012 title runner-up Pedrosa was only eighth fastest for Honda on Thursday, with rookie team-mate Marc Marquez the top non-Yamaha rider in fourth (+0.591s).

"It's a good beginning and the bike is working very well. This circuit really suits the YZR-M1," confirmed team director Massimo Meregalli. "To see both riders consistently leading the practices means something positive. We'll check the data now and make some small adjustments and see where we can go."

The final two free practice sessions will be held on Friday night.