Valentino Rossi broke the pre-season dominance of Dani Pedrosa and Jorge Lorenzo by setting the pace during day two of the final MotoGP test at Jerez on Sunday.
Pedrosa (5) and Lorenzo (2) had led all previous days of official 2013 testing, including Saturday's wet start at Jerez, when Lorenzo was quickest.
However it was seven time MotoGP champion Rossi - returning to Yamaha after two poor seasons at Ducati - who made the best of dry track time on Sunday afternoon.
Rossi's fastest lap, of 1m 39.525s, was several tenths under the official race record and kept Lorenzo at bay by just 0.015s. Tech 3 Yamaha's cal Crutchlow was a fraction slower in third, with Pedrosa the leading Honda in fourth (+0.105s).
Sunday marked the first time that Rossi has outpaced reigning double champion Lorenzo since re-joining the factory M1 team last November.
"It's not important, but it's very important!" Rossi said of being fastest. "I'm so happy, not just because of the position, but also because we modified some of the settings to adapt the M1 more to my style.
"It is very important for us to understand this setting, which can help and effect my riding style - to ride the bike in a better way and stay more constant, especially with good lap times on old tyres.
"To make the first position with a time of 39.5 is good and also being as fast as Jorge. Me and my team are very happy with the pace and I think we will try to continue to work on this way.
"For tomorrow, we have a new chassis with some small differences, so both Jorge and I will try it. We hope to be able to improve our level a bit."
Team director Massimo Meregalli confirmed that Rossi and Lorenzo will make a decision on which chassis specification to use in Qatar's opening round following Monday's final day of pre-season testing.
“We were able to work very well on the base set up and we had quite good results,” he said. “Now we are ready to test the last new items tomorrow. We will confirm the difference between the two chassis' and decide which one to use in Qatar.”