Lorenzo moved to the head of the times with six minutes remaining on his Ducati, putting him a tenth of a second ahead of home hero Cal Crutchlow at the time.
However Vinales, who held first position before Crutchlow’s lap, and then abandoned an attempt that was just 0.001s down on the Briton after three sectors, reappeared at the end of the session to post a lap half a second clear of the field as the checkered flag flew.
That left Lorenzo second and Crutchlow third at the end, with early-session pacesetter Marc Marquez fourth ahead of Valentino Rossi.
Alvaro Bautista (Aspar Ducati) was another rider to improve at the end to move up to sixth, knocking back Johann Zarco (Tech 3 Yamaha), who had claimed the place moments earlier.
They were followed by Aprilia’s Aleix Espargaro and another home rider Scott Redding (Pramac Ducati), who also jumped into the top 10 at the flag.
Championship contender Andrea Dovizioso was next up, 1.2s adrift of the pace set by Vinales.
Of the championship frontrunners, Dani Pedrosa was noticeably quiet, ending the session in 14th place.
Sam Lowes (Aprilia) was the only rider to crash in FP1, losing the front through the high-speed Farm curve, and while he rejoined on another bike later on, he ended up at the bottom of the order.
Danilo Petrucci (Pramac Ducati) also hit trouble towards the end, coming to a stop just before Club and pulling up at the entry to the Formula 1 pitlane.