Honda rider Dani Pedrosa led Ducati's Jorge Lorenzo in the second MotoGP practice session at Aragon.
Pedrosa posted a 1m59.858s effort, the weekend's only laptime under two minutes so far, on a damp circuit.
Track conditions at the start of the session mirrored those from first practice, and it was again Marc Marquez who prospered initially, bettering his FP1 benchmark with a 2m00.933s lap a third of the way into FP2.
This left him around a second clear approaching halfway point, before title rival Andrea Dovizioso mustered a lap just 0.029s slower.
But Marquez responded instantly, lowering the time to 2m00.459s, with teammate Pedrosa slotting in behind with a lap 0.083s off shortly thereafter.
The pair remained out front until the closing minutes of the session, LCR's Cal Crutchlow briefly making it a Honda 1-2-3, before Lorenzo split Marquez and Pedrosa on the timing screens.
Lorenzo's next lap, a 2m00.072s, took him to the top spot, only for Pedrosa to then breach the two-minute barrier.
Tech 3 Yamaha's Johann Zarco moved up to third at the chequered flag, demoting Marquez, who had opted against a last-gasp flying lap.
Karel Abraham was fifth for Aspar Ducati, ahead of Crutchlow and Aprilia rider Sam Lowes, while Dovizioso led Espargaro brothers Aleix and Pol in eighth.
Valentino Rossi, making an earlier-than-expected return to track action this weekend after breaking his leg in late August, was mixing it among the frontrunners for much of the session, but ended up 20th, two seconds down.
His Yamaha teammate Maverick Vinales, on the other hand, was firmly among the backmarkers before a late improvement put him 17th.
Both Vinales and Rossi are thus outside of the top 10 on combined practice times and are not currently on course to automatically progress to Q2, although the weather is expected to improve for Saturday's track action.