Nicky Hayden lowered his lap time by almost one-second during day two of private testing at Jerez, putting the Ducati rider under this week's best WSBK lap in the process.
The American, the only factory Ducati MotoGP rider on track with team-mate Andrea Dovizioso
still struggling with a neck strain, improved from a 1m 40.855s on Wednesday to a 1m 40.090s on Thursday, despite a small fall.
That beat the 1m 40.185s by Aprilia WSBK star Eugene Laverty, set with qualifying tyre on Wednesday. Laverty and Kawasaki's Tom Sykes both set a 1m 40.4s with race tyres. The Jerez MotoGP race lap record is a 1m 39.731s.
The fastest of the WSBK riders still present on Thursday - Aprilia, Kawasaki and Honda having left - was BMW's Marco Melandri
with a time of 1m 40.816s.
Pramac Ducati MotoGP rookie Andrea Iannone was a fraction slower than Melandri with a 1m 40.989s, followed by new Ducati test rider Michele Pirro, riding in place of Ben Spies, with a lap of 1m 41.265s.
The last test of 2012 concludes on Friday, with Dovizioso hoping to salvage some track time on the final day.