Repsol Honda dominated the first two practice sessions of the Aragon Grand Prix, with Dani Pedrosa fastest on Friday.
Fresh from his first victory of the season at the San Marino Grand Prix last time out, Pedrosa clocked the best lap of the day at one minute and 48.429 seconds.
The Spaniard was outside the top 10 in the first session but outpaced team-mate and championship leader Marc Marquez in FP2 by over six hundreths.
LCR Honda rider Cal Crutchlow was third fastest, with Valentino Rossi (Movistar Yamaha) and Pol Espargaro (Monster Yamaha) rounding out the top five of FP2.
British Grand Prix winner Maverick Vinales (Suzuki Exstar) came in sixth, with the man he will replace at Movistar Yamaha next season, Jorge Lorenzo, in seventh.
Andrea Iannone (Ducati) ended FP1 - led by Marquez - in sixth position but announced he would not take part in the remainder of the grand prix as he continues to recover from vertebra damage at the San Marino Grand Prix, test rider Michele Pirro taking his place.
The Suzuki Ecstar of Aleix Espargaro suffered considerable damage following a crash in the afternoon session.