Quartararo starts well
Quartararo began the day as the man to beat, but San Marino GP winner and team-mate Franco Morbidelli (Petronas Yamaha SRT) made for close company as he ended the session within 0.090.
It was a rapid start to proceedings for the premier class riders, with Quartararo's quickest time just three tenths away from Maverick Vinales' (Monster Energy Yamaha MotoGP) lap record set in Q2 last weekend.
Nakagami makes a move
Nakagami hit next to go top, by 0.069, as the Japanese rider's improvements in testing kept impressing.
Nakagami and Honda have seemingly found some of the issues that plagued the Japanese rider last weekend at Misano and having finished P5 in FP1, Nakagami was then leading the way.
Vinales revves up
Tucked in behind lap record holder Vinales, the Brno winner demoted Nakagami to P2 by 0.002 seconds - leaping up the timesheets after P14 in the morning.
Vinales, just ahead of the South African on track, went to P4 after choosing not to do a time attack run in FP1.
Espargaro slips
Pol Espargaro's 1:31.699 eventually saw him slip to fifth and at the end of the session, you could throw a blanket over the top five - it was that close.
Just 0.071 between three manufacturers is a timely reminder of how close the premier class is in 2020!