Honda's Dani Pedrosa set the pace on Thursday, the final day of the second MotoGP test at Sepang in Malaysia, while his new teammate Marc Marquez took second on a slippery circuit.
The gap between the two Spanish riders was just 0.081 seconds and the pair edged out their traditional Yamaha rivals, Jorge Lorenzo and Valentino Rossi.
After heavy overnight downpours, top riders including Lorenzo, Pedrosa, Marquez and Rossi earlier in the day had a chance to test their bikes' handling on a damp track on wet-weather tyres.
Conditions vastly improved in the afternoon, and Pedrosa took advantage by pushing his bike hard for a total of 57 laps to notch the fastest time of two minutes 00.562 seconds.
Lorenzo, a double MotoGP champion, came in third 0.430 seconds off the pace.
Marquez has been consistently fast since the first pre-season test sessions at Sepang three weeks ago. The MotoGP rookie continued to make impressive progress despite crashing twice in the day. He was unhurt.
Lorenzo's team-mate, nine-times world champion Valentino Rossi, was fourth at two minutes 01.062 seconds.
Spain's Alvaro Bautista on a Honda was fifth while British Yamaha rider Cal Crutchlow took sixth.
Pedrosa, 27, who is in top form and hungry for a MotoGP title, topped the timesheets during both test sessions this month, apart from on Wednesday when Lorenzo took the honours.
While track conditions this week were a little worse than early this month, he said they allowed him to learn more about the bike's performance.
"We did a good test overall. The basics of the bike is quite good," Pedrosa said.
Pedrosa made his debut in 2006 but has never won a world championship for Honda, largely due to injuries. He has been runner-up for the MotoGP title on three occasions.
Lorenzo acknowledged he needed to improve his performance. "We had a problem in the front tyre. I had to slow down a bit my pace," he said.
He said the slippery track also hampered his attempt to set a faster pace than Wednesday, when he topped the timesheet. "If it had not rained last night, I am sure I could have improved the lap time from yesterday."
Italy's Andrea Dovizioso on a Ducati came in eighth, just behind Honda's Stefan Bradl of Germany.
"We are slow in the middle of the corner. At this moment we do not have the capacity to fight Honda and Yamaha but I am really happy with how much we have improved with the bike," Dovizioso told reporters.
A third session will be held in Jerez from March 23 to 25 before the opening round of the MotoGP world championship in Qatar under floodlights on April 7.
Malaysia will host round 15 on October 13.
