to view full Free Practice 1 results for the Catalunya MotoGP.
Local star Aleix Espargaro finished opening practice for the Catalunya MotoGP with a 0.7s advantage over countryman Jorge Lorenzo.
However Forward Yamaha rider Espargaro, who grew up just a few kilometres from the Barcelona circuit and will unveil a special livery later in the weekend, used the special Open class soft rear tyre to set his scorching 1m 41.672s, already 0.7s under the official race lap record.
Espargaro had improved by one-second with the soft rear rubber and it was defending Catalunya winner Lorenzo who led most of the session, just 0.022s ahead of Movistar Yamaha team-mate Valentino Rossi.
Pramac Ducati's Andrea Iannone then split the M1s with a late lap on his soft rear, not available to the Factory class Honda and Yamaha riders, but then fell after running off track at the end of the back straight when his Desmosedici got out of shape under braking.
LCR Honda's Stefan Bradl was demoted from third to fifth by the soft tyre laps, with Repsol Honda's Dani Pedrosa - pole and race lap record holder - the final rider within one-second of Espargaro.
Team-mate and countryman Marc Marquez began his quest for a perfect seventh win of the season with seventh, but only 0.341s behind Lorenzo. Lorenzo came the closest yet to beating Marquez in 2014 last time in Italy.
Alvaro Bautista (Gresini Honda), Yonny Hernandez (Pramac Ducati) and Aleix's younger brother Pol Espargaro (Monster Yamaha Tech 3) completed the morning top ten, when air temperatures were already over 30 degrees.
Factory Ducati riders Andrea Dovizioso and Cal Crutchlow, who do not believe the heat will allow them to race with the soft rear on Sunday (when there is also a significant chance of rain) were only eleventh and 15th, with test rider and Catalunya wild-card Michele Pirro in twelfth.
Bradley Smith was another notable name outside of the top ten, in 13th on his Tech 3 machine.
Cardion AB's Karel Abraham backed up his impressive Mugello ride to be the top Production Honda rider, in 14th. Gresini rookie Scott Redding was next best in 16th while Aspar's Nicky Hayden made his return from wrist surgery with 17th.
The former world champion is due to assess his fitness following FP1, when he completed 15 laps with a best (on lap 14) 2.336s behind Espargaro.
Michel Fabrizio is again replacing the injured Danilo Petrucci at Ioda and completed the timesheets in 24th.
Free Practice 1:
1. Aleix Espargaro
2. Jorge Lorenzo
3. Andrea Iannone
4. Valentino Rossi
5. Stefan Bradl
6. Dani Pedrosa
7. Marc Marquez
8. Alvaro Bautista
9. Yonny Hernandez
10. Pol Espargaro
11. Andrea Dovizioso
12. Michele Pirro
13. Bradley Smith
14. Karel Abraham
15. Cal Crutchlow
16. Scott Redding
17. Nicky Hayden
18. Colin Edwards
19. Hector Barbera
20. Michael Laverty
21. Hiroshi Aoyama
22. Broc Parkes
23. Mike Di Meglio
24. Michel Fabrizio