Suzuki MotoGP riders Alex Rins and Joan Mir ended the opening day of pre-season testing in Qatar first and second – and separated by a mere 0.002 seconds.
Mir was able to set his time as the floodlights came on and the Losail circuit cooled down, but it was a last-minute flying lap from Rins, the final lap of the day, that took the top spot.
Qatari resident Maverick Viñales was third, top Yamaha on a good day for the manufacturer that also meant Franco Morbidelli finish fifth and Valentino Rossi seventh.
Fabio Quartararo, fastest at the Sepang test two weeks ago, had the rare honour of finishing last of their four machines but still inside the top ten in eighth.
Danilo Petrucci was fourth, sticking in a late time of his own to salvage what was otherwise a disappointing day for the Italian manufacturer.
Team-mate Andrea Dovizioso was 11th after suffering a minor fall, while Pecco Bagnaia and Jack Miller were ninth and 13th.
Marc Marquez ended the day in sixth, still recovering from complications with his shoulder surgery.
Able to briefly top the timing screens in the afternooon, he nonetheless finished 0.3 seconds from his fellow Spaniard Rins.
Rookie teammate and little brother Alex was 21st, while Cal Crutchlow was a distant 19th.
Aleix Espargaro was the best of the concession factory riders, finishing the day inside the top ten for Aprilia. His brother Pol, who joined him at the top of the screens earlier in the day, was top KTM in 14th.
Testing continues tomorrow at Losail for the second of three planned days.