Mercedes left it late to post the two quickest times of final practice ahead of the Brazilian Grand Prix, with Nico Rosberg edging Lewis Hamilton to top the timesheets.
Hamilton, who has never won at Interlagos, had gone quickest in the opening two sessions on Friday as he looks to deny Rosberg - leading the drivers' standings by 19 points - a maiden world title this weekend.
Victory on Sunday will see Rosberg dethrone Hamilton as champion.
Mercedes opted to focus on their long runs for the most part on Saturday, with Rosberg posting his time of one minute and 11.740 seconds with 10 minutes to go.
Hamilton was less than a tenth down on Rosberg, ahead of Ferrari duo Sebastian Vettel and Kimi Raikkonen, as well as Max Verstappen and Daniel Ricciardo of Red Bull.
Elsewhere on the grid, McLaren's Fernando Alonso eventually got some laps under his belt after gearbox trouble threatened to curtail a second session in a row for the Spaniard, while Marcus Ericsson's participation in qualifying could be in doubt due to an engine problem.
The clear skies of Friday disappeared behind grey clouds that dampened the track in the build-up to the final session, but drivers reported that the circuit had not become too wet in the shower.
The rain is expected to carry on into Sunday, so one spectator may need to purchase a new umbrella after one found its way onto the track early in FP3, bringing out the yellow flags.