Jorge Lorenzo headed the times in the first practice session for the final MotoGP race of the season at Valencia, leading teammate Valentino Rossi in a Yamaha 1-2.
It was the Honda of Marc Marquez that commanded most of the 45-minute session, as the three-time champion took control of the leaderboard with an early 1m32.308s before steadily working his way down to a 1m31.841s at the halfway point.
With 15 minutes to go, the Repsol Honda man improved to a 1m31.442s, which looked set to be the benchmark time of the session before both Yamaha riders found considerable time in the closing minutes.
First, Lorenzo set a blistering time of 1m31.072s to go a full three tenths faster than Marquez, before going quicker still with a 1m31.045s on the next lap.
While Rossi was unable to match his teammate, the Italian's final effort of 1m31.432s was just enough to eclipse Marquez and make it two Yamahas at the head of the times, 0.387s behind Lorenzo.
At the start of the session, Rossi lost around 15 minutes of track time as his factory M1 bike spluttered to a halt on his out-lap - forcing him to hitch a lift back to the paddock and jump on his spare machine.
Behind the leading trio, Sepang winner Andrea Dovizioso was fourth fastest for Ducati, 0.487s behind future teammate Lorenzo, followed by the Tech 3 Yamaha of Pol Espargaro.
The works Suzukis of Maverick Vinales and Aleix Espargaro were next up in sixth and seventh, followed by Jack Miller on the second-best of the Hondas, Scott Redding's Pramac Ducati and Andrea Iannone on the second works bike.
Taking part in his first session since last month's Japanese Grand Prix, the returning Dani Pedrosa was 12th fastest on the second Repsol Honda, 1.408s off the pace and just over a second off teammate Marquez.
Mika Kallio, giving the KTM RC16 its official competitive debut, ended up slowest of all despite some encouraging early times, 2.940s off the pace and around half a second behind the next slowest competitor, the Avintia Ducati of Loris Baz.
First practice results: