Ricciardo moved up to fifth by second practice, with Max Verstappen less than two tenths of a second behind in seventh.
"Our race pace was very strong, we need to look into the short run anyway," Verstappen said. "After missing first practice almost entirely I was still working a lot on the car and finally before the long run I made a final set-up change and that seemed to work pretty well."
Ricciardo, meanwhile, thinks that the team can unlock a bit more pace before Sunday's race.
"Reliability and everything for that today was pretty good, we did a lot of laps which was positive, we still want to find some more speed, it wasn’t the perfect day for wheel performance but I think we definitely run a lot so it gives us something to look forward to."
Bahrain International Circuit - Winter testing