Marco Melandri got his seventh World Superbike Championship round off to an ideal start as he paced first free practice at Motorland Aragon.
The Italian, who is one of only two riders in the field to have previously raced at the Alcaniz venue, also made the most of having tested at the circuit recently as he edged out local favourite Carlos Checa in the opening session.
Hitting the front with 15 minutes remaining, Melandri lowered his personal best on a further two occasions to end with a 1min 59.822secs, just under a tenth quicker than Checa, the only other man below two minutes.
Having come remarkably close to a maiden WSBK podium at Misano less than a week ago, BMW Italia's Ayrton Badovini picked up where he left off with the third quickest time. Not only did he emerge as the highest-placed BMW rider, but he was well ahead of his factory counterparts, Leon Haslam and Troy Corser down in 14th and 16th.
British pairing Leon Camier and Tom Sykes crept into the top five aboard their respective Aprilia and Kawasaki bikes, while Suzuki's Michel Fabrizio shrugged off his arm complaint to be sixth fastest, in doing so ensuring six different manufacturers featured inside the top six.
Max Biaggi challenged Checa during the early stages of the session, despite falling within the first five minutes, but would eventually slip to seventh best, while Jakub Smrz, Maxime Berger and Eugene Laverty rounded out the top ten.
A fairly bruising session for some riders, as well as Biaggi, Joan Lascorz, Noriyuki Haga, Roberto Rolfo and Ruben Xaus all suffered tumbles, though each was unharmed.