Force India's impressive weekend at the European Grand Prix in Baku suffered a blow when Sergio Perez collided with a wall in the final seconds of Practice Three.
Lewis Hamilton and Nico Rosberg filled the top two spots in the timesheets for the third consecutive practice session, with the Englishman's mark of 1:44.352 just under three tenths of a second better than that of his Mercedes team-mate.
Nico Hulkenberg was third for Force India, following up on Perez's top-three finish from Practice Two.
But that excitement was dampened by the Mexican colliding with the wall on turn 15, leaving the team with a race against time to repair damage to the rear of his car before qualifying, while hoping to avoid a gearbox change that would come with a grid penalty.
Hamilton will also be anxious to avoid punishment after McLaren's Jenson Button complained he was held up by the Mercedes as he attempted a late flying lap.
Despite the FIA having made changes to the kerbs at turns 6 and 12 to reduce cuts in tyres as well as tweaks to the pit-lane entry after complaints from drivers, teething problems at the new track continued.
Damage to Valtteri Bottas' Williams was caused when a cable-duct cover came loose in the pit lane, leaving the car with a large hole that ended the Finn's session before he was able to set a time.
Red Bull improved from their struggles on Friday with Daniel Ricciardo fourth and Max Verstappen seventh, pleasing team boss Christian Horner.
"It is definitely progress from Friday," he said to Sky Sports.
"Bar the paint-work, we have changed everything on the cars. The engineers had a long night but they have come up with a set-up that the drivers are comfortable with."
Sebastian Vettel was fifth for Ferrari with Perez coming sixth, but Kimi Raikkonen suffered engine issues that meant he ended in 10th spot.
Mercedes are way ahead of the pack in Azerbaijan, but there appears to be little between Force India, Red Bull and Ferrari with an intriguing qualifying session now in store.