Jorge Lorenzo dominated a dry and sunny warm-up session for the Aragon MotoGP, which saw title rival Dani Pedrosa break an all-Yamaha top four on his final lap.
After three wet free practice sessions, then a dry but cold qualifying, the best weather of the weekend arrived for race day morning.
Pole sitter Lorenzo was quick from the start - Factory Yamaha team-mate Ben Spies being the only rider within two-seconds of the world championship leader as the halfway stage of the 20-minute session approached!
Lorenzo and Spies went on to set their best time on their last lap, with Lorenzo getting the edge by 0.018s.
By contrast Lorenzo's title rival Dani Pedrosa had been 15th and five seconds off the pace by the midway, before breaking into the top ten with five minutes to go. The Repsol Honda rider went on to claim third, 0.251s from Lorenzo, on his tenth and final lap with the soft tyres front and rear.
That broke the M1 domination, pushing Yamaha Tech 3 riders Andrea Dovizioso (+0.4s) and front row starter Cal Crutchlow (+0.7s) to fourth and fifth.
LCR Honda's Stefan Bradl was the final rider within one second of Lorenzo, with Nicky Hayden the lead Ducati rider in seventh (+1.287s).
Alvaro Bautista (Gresini Honda), Valentino Rossi (Ducati) and Randy de Puniet (Aspar CRT) completed the top ten.
Pramac Ducati's Hector Barbera was the only faller, tumbling roughly from his Desmosedici after running wide and losing the front. The Spaniard walked away.
Repsol Honda stand-in Jonathan Rea was twelfth, with Cardion AB Ducati's Karel Abraham the slowest of the manufacturer riders in 13th.
Lorenzo will start this afternoon's race, round 14 of 18, with a 38-point lead over Dani Pedrosa.
The improving weather will complicate tyre choice for the grand prix, with the harder tyres back in contention.
1. Jorge Lorenzo
2. Ben Spies
3. Dani Pedrosa
4. Andrea Dovizioso
5. Cal Crutchlow
6. Stefan Bradl
7. Nicky Hayden
8. Alvaro Bautista
9. Valentino Rossi
10. Randy De Puniet
11. Hector Barbera
12. Jonathan Rea
13. Karel Abraham
14. Aleix Espargaro
15. Mattia Pasini
16. Colin Edwards
17. Yonny Hernandez
18. James Ellison
19. Michele Pirro
20. David Salom
21. Danilo Petrucci