Mercedes took command of the field in Friday's second free practice session in Abu Dhabi, with Valtteri Bottas leading teammate Lewi Hamilton by 0.203s.
The Red Bull pair of Max Verstappen and Alex Albon followed the Black Arrows duo by less than a second while Lando Norris in P5 improved McLaren's performance in FP2.
Friday's second work session kicked off with the sun dipping below Abu Dhabi's horizon, but ambient and track temperatures were still a warm 24.7°C and 31.8° respectively.
Kevin Magnussen and Antonio Giovinazzi were reunited with their respective cars after both drivers sat out FP1 for the benefit of their Haas and Alfa substitutes.
But the session - more relevant because of conditions likely similar to those drivers will encounter on race day - also offered everyone other opportunity to test a set of Pirelli's much decried 2021 tyre, in this case the C4 compound. Each driver needed to complete at least eight timed laps on the rubber.
Bottas proved the fastest runner on the prototype tyre, while Hamilton the first to revert to the current medium tyre, a swap that duly pushed him to the top of the timesheet.
However, the Briton was overhauled in short order by Bottas who lowered the benchmark to 1m36.276s.
Forty-five minutes into the session, the bulk of the field switched its focus to the soft tyre and to qualifying sims during which a fair number time deletions for track limit violations were recorded.
Bottas and Hamilton remained in charge with unchanged times, the pair leading Verstappen, Albon and Norris. But Mercedes' drivers than switched back to the 2021 prototype tyre as neither had completed the required eight timed laps earlier in the session.
Unequivocal signs that the season was reaching its end were displayed when Russell was told to back off and pit his smoking Williams, its engine obviously on its last legs.
No sooner had the Briton pulled in that Kimi Raikkonen's Alfa was seen on fire, the Finn parking his car on the exit of Turn 7 to allow the engine blaze to be extinguished.
The session was subsequently red flagged with less than 15 minutes left on the clock, while engine change plans were suddenly devised in the Williams and Alfa Romeo camps.
The halt undermined the long run plans of most teams, a setback that didn't provide much clarity regarding the potential running order in race trim.
The session resumed with just a few minutes in hand, but no improvements were in store, the day concluding with a Mercedes 1-2 and Bottas leading Hamilton by 0.203s.
Red Bull's Verstappen and Albon remained P3 and P4, less than a second behind while Norris and Ocon completed the top six.
Perez, Leclerc, Ricciardo and Stroll closed out the first half of the field, with the Renault driver putting 27 laps under his belt after his botched FP1 session.
AlphaTauri's Daniil Kvyat finished his evening P11, the Russian edging Sainz, teammate Gasly and Raikkonen,
Sebastian Vettel was a lowly 15th while Magnussen, Giovinazzi, Russell, Fittipaldi and Latifi made up the rear.