A late surge moved Valentino Rossi
from eighth to first during Friday's second practice session for the Catalunya MotoGP.
The Italian, fourth fastest this morning, was using the softer option rear tyre when he dipped 0.049s under Yamaha team-mate and home hero Jorge Lorenzo.
The result marked the first time that seven time MotoGP champion Rossi has led a session since returning to Yamaha at the start of this year.
Lorenzo had been quickest in FP1 and led almost all of the afternoon session, setting his best time on lap three and remaining in charge until Rossi's late push.
Repsol Honda's world championship leader Dani Pedrosa
and Monster Yamaha Tech 3's Cal Crutchlow did not improve in the afternoon - when track temperatures reached 49 degrees - but the pair were still third and fourth on combined Friday times courtesy of their FP1 efforts.
Gresini Honda's Alvaro Bautista put his morning fall behind him by moving up to fourth in the afternoon session, which saw him holding second to Lorenzo for substantial periods.
Repsol Honda's rookie star Marc Marquez also moved forwards, from ninth to sixth, cutting the deficit to the front from 1.219s to 0.560s in the process. Lorenzo, Pedrosa and Marquez will all be battling for home glory on Sunday, in what is the most local of the Spanish rounds for the title top three.
Nicky Hayden edged out team-mate Andrea Dovizioso
by 0.098s to be the lead Ducati, in seventh, during FP2. Stefan Bradl suffered a fall on his way to ninth for Honda LCR, with top CRT rider Aleix Espargaro tenth and just 0.9s from Rossi.
Bradley Smith, riding with an injured hand, was helped away by marshals after falling just before the midway mark. The Monster Yamaha Tech 3 rider finished the session in 14th, having not returned after the fall.Free practice 2:
1. Valentino Rossi
2. Jorge Lorenzo
3. Dani Pedrosa
4. Alvaro Bautista
5. Cal Crutchlow
6. Marc Marquez
7. Nicky Hayden
8. Andrea Dovizioso
9. Stefan Bradl
10. Aleix Espargaro
11. Andrea Iannone
12. Randy De Puniet
13. Michele Pirro
14. Bradley Smith
15. Hector Barbera
16. Colin Edwards
17. Karel Abraham
18. Danilo Petrucci
19. Michael Laverty
20. Claudio Corti
21. Hiroshi Aoyama
22. Yonny Hernandez
23. Bryan Staring
24. Lukas Pesek