World Superbike star Jonathan Rea, set to make his MotoGP debut in place of injured MotoGP champion Casey Stoner at the forthcoming Misano round, moved a few tenths closer to the front during the start of his second test for Repsol Honda.
3.145s from the top at the end of the Brno test, Rea cut the deficit to 2.696s on day one of the private two-day Aragon outing, which is being attended by the factory Honda and Yamaha teams, plus LCR Honda's Stefan Bradl.
Rea, who raced his Ten Kate Honda at the Spanish circuit in June, rode for 69 Tuesday laps.
"Today I was just getting a good feeling between me and the machine because it still feels very strange,” said the 25-year-old Ulsterman.
"I had to work a lot on my brake style today; normally in Superbike I don't use so much rear brake but here it seems that I have to learn to use it in every corner!
"Just concentrating on this and getting a better setting on the brakes and trying to do longer runs on the tyres because for me it's very different at the end.
"I feel comfortable on the bike, the riding position is good, but I just need to understand how the traction control is working, what happens when the tyres drop down and be more comfortable with the set-up".
Repsol Honda's title contender Dani Pedrosa led the way on day one, with Rea just over one-second from the best time by MotoGP rookie Bradl.
The Aragon test concludes on Wednesday evening, after which Rea's next MotoGP appearance - barring a return from ankle surgery by Stoner - will be during Friday practice for the San Marino Grand Prix at Misano on September 14.