Ducati factory rider Andrea Dovizioso topped the third MotoGP free practice session in Barcelona, as a costly late crash condemned championship leader Marc Marquez to a Q1 appearance.
Marquez was within the combined practice top 10 when he fell while braking hard into the sharp Turn 10 left-hander in the dying minutes of FP3 while on a push lap.
And when Dovizioso put in a late lap to top the session, Marquez was denied an automatic Q2 spot.
The Spaniard will now have to fight through Q1 for the first time since the Mugello round of the 2015 season.
The reigning champion had already begun the day outside the combined top 10 – but took no time to force himself in, kicking off FP3 with his first run with a soft rear tyre this weekend.
He set an initial 1m39.705s before swiftly lowering that to 1m39.390s, which left him comfortably quickest until the late-session qualifying simulation runs.
Avintia Ducati's Tito Rabat, who spent much of FP3 as runner-up to Marquez, took over at the top with eight minutes left on the clock, as he followed Dovizioso through the lap.
Yamaha's Valentino Rossi went quickest shortly thereafter, narrowly surpassing Rabat with a 1m39.234s before Tech 3's Johann Zarco fired in a 1m39.143s.
This was bettered by LCR Honda rider Cal Crutchlow, who had crashed at Turn 2 earlier in the session, before a last-ditch effort from Dovizioso – a 1m38.923s – sealed FP3 honours for the Italian, as he narrowly beat teammate Jorge Lorenzo's Friday benchmark in the process.
Yamaha's Maverick Vinales lapped within a tenth of Dovizioso to slot into second at the chequered flag, ahead of Crutchlow, Zarco, Rossi and Pramac Ducati's Danilo Petrucci.
Marquez's Honda teammate Dani Pedrosa was seventh in the session, leading Rabat, Marquez himself and Tech 3's Hafizh Syahrin.
But it was Lorenzo and Suzuki's Andrea Iannone progressing to Q2 automatically at Marquez and Syahrin's expense, with the former pair's Friday times enough to comfortably assure them of a spot in the combined top 10.
Marc VDS Honda rider Franco Morbidelli, who elected to go to the hospital on Friday after hurting his neck in a hard FP2 fall, was a solid 17th – despite crashing late on in the session for what was his third accident in three practice sessions so far.