Dani Pedrosa came out on top in FP2 at Aragon as Honda riders completed a dominant 1-2-3 on Friday.
Pedrosa, fresh from his first victory of the season in the previous round at Misano, only just edged out team-mate and FP1 pacesetter Marc Marquez by 0.065s for the top spot with a lap in 1m 48.429s.
Britain's Cal Crutchlow was in the mix again on the LCR Honda as he slotted into third position behind the factory duo, only a further 0.081s in arrears after a lap in 1m 48.510s as Aragon's reputation as a 'Honda track' remained firmly intact on day one.
Movistar Yamaha's Valentino Rossi, second fastest in the morning, was fourth on the YZR-M1, 0.241s down on Pedrosa.
The nine-time world champion was pursued by Pol Espargaro on the Monster Tech 3 Yamaha, with Silverstone winner Maverick Vinales completing the top six on the Ecstar Suzuki. Espargaro was among several riders caught out at Turn 2, including his brother Aleix, Eugene Laverty and Alex Lowes.
Reigning world champion Jorge Lorenzo, who has won the past two MotoGP races at the Spanish circuit, was seventh fastest, 0.485s off Pedrosa's pace.
The top 10 was completed by a trio of Ducati riders headed by Avintia Racing's Hector Barbera, with Danilo Petrucci on the Pramac machine next ahead of factory rider Andrea Dovizioso.
Aleix Espargaro (Ecstar Suzuki) ended the session in 11th place ahead of Colombian Yonny Hernandez on the Aspar Ducati.
Gresini Aprilia pair Stefan Bradl and Alvaro Bautista were 13th and 14th quickest respectively in front of Michele Pirro, who again fills in for the injured Andrea Iannone on the factory Ducati Desmosedici GP16.
Scott Redding was next up on the Pramac Ducati ahead of Irishman Laverty (Aspar Ducati) and Tito Rabat on the Marc VDS Honda, whose team-mate at Aragon – World Superbike rider Nicky Hayden – was 21st fastest as the American stands in for injury victim Jack Miller.
Briton Lowes, who is the injured Bradley Smith's replacement in the Monster Tech 3 Yamaha team for the third successive race, was 20th fastest.
1. Dani Pedrosa
2. Marc Marquez
3. Cal Crutchlow
4. Valentino Rossi
5. Pol Espargaro
6. Maverick Viñales
7. Jorge Lorenzo
8. Hector Barbera
9. Danilo Petrucci
10. Andrea Dovizioso
11. Aleix Espargaro
12. Yonny Hernandez
13. Stefan Bradl
14. Alvaro Bautista
15. Michele Pirro
16. Scott Redding
17. Eugene Laverty
18. Tito Rabat
19. Loris Baz
20. Alex Lowes
21. Nicky Hayden
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