Factory Yamaha riders Jorge Lorenzo and Ben Spies both moved up the timesheets on the second night of practice, but insisted that a victory challenge in Sunday's season-opening race is unlikely.

Sixth (Spies) and seventh (Lorenzo) after Thursday's session, the M1 riders held fourth and fifth by the conclusion of the third and final free practice session on Friday night.

Both look strong on long runs and were close to third-fastest Andrea Dovizioso, but the other two Repsol Honda riders - Casey Stoner and Dani Pedrosa - remain over three-quarters of a second ahead in terms of ultimate lap time.

"We are struggling to fight with some of our competitors but we won't give up, we will continue to work on it and see if we can find another half a second tomorrow," said world champion Lorenzo.

"I will try to make a good qualifying session to start on the front row. It will be a long race and we have a good race pace so I think we have a chance to finish on the podium."

Spies, preparing to start his first race as a factory MotoGP rider, has the same top-three goal.

"We've made some good changes and we're confident with the bike set up, maybe not for winning the race but definitely good enough for top five and maybe a podium," he said. "We know we need a little work but we'll keep on at it and see where we can get to."

The one-hour qualifying session will be the only MotoGP track action on Saturday.