Lorenzo Baldassarri topped the final Moto2 practice session ahead of qualifying at Jerez fastest by almost four tenths of a second after going underneath the outright lap record.
Friday pacesetter Alex Marquez shot to the top of the pile in the early stages of FP3 with a 1:42.404s, improving on his best from FP2 by just over a tenth of a second, while Brad Binder slotted into second by just 0.010s.
Marquez's time remained as the benchmark until the final 20 minutes, when Sam Lowes guided his CGBM Evolution KTM to a 1:42.365s.
However, the Briton's time at the front last all of a minute, as Jorge Navarro went just over a tenth quicker on his Gresini Kalex.
Baldassarri deposed the Spaniard moments later with a 1:42.206s, before cementing his position at the head of the field in the closing minutes with a brace of unofficial lap records, the second of which a 1:41.890s.
This put the Pons rider almost four tenths ahead of the rest, and remained unchallenged as the chequered flag was brought out.
Navarro held onto second spot, while Italtrans rider Mattia Pasini leaped up to third at the end with a 1:42.310s, nudging Lowes back a spot to fourth.
Marquez was knocked back to fifth after a late fall at Dry Sac. The Spaniard was able to remount, but failed to extract any more laptime from his damaged Marc VDS machine.
Brad Binder was a further 0.010s back from Marquez in sixth, with Romano Fenati heading Marcel Schrotter, championship leader Francesco Bagnaia and a late-charging Danny Kent to complete the top 10.
Miguel Oliveira, who will step up to the MotoGP class next season after agreeing a deal to join the Tech3 KTM squad, was a low-key 13th in final practice.
