Lewis Hamilton was fourth quickest on a circuit where he has tasted the victory Champagne on six different occasions, including the last three consecutive years.
Ricciardo won in Monaco despite nursing an engine problem so terminal that his Red Bull boss Christian Horner likened it to the troubling Apollo 13 space mission.
"We had what looked like an electrical problem", he confirmed. The Monaco Grand Prix victor set the fastest first sector of the session before a lock-up at the tight hairpin at the start of sector three cost him significant time on what proved to be his personal best lap.
"I'm very happy with this weekend so far". "Track fix required between Turns Four and Five", said a message from Race Control meaning a drain cover needed fixing between Casino Square and Mirabeau.
From the start, Verstappen nearly got the jump on Bottas, but the Finn held his line around the outside of Turn 1 to take the inside line into the next corner, keeping hold of second spot. But then to a position below it moved ricciardo, who was third in 0.4 seconds from Verstappen. "If we got in that mess around here on this circuit, it is not as bad as Monaco but it is still very hard to make much progress here".
"I feel like we were always kind of one step back, I think we got our stuff together in qualifying and I felt the laps were worth more than a sixth place, but in the end they weren't", he added. When you feel confident with the vehicle then you can do a good job. "Our auto works well, but whether that will be enough in Q3, I don't know".
"I would say that Mercedes' pace was really fast today", Ricciardo said.
But after the dreary spectacle in Monaco a fortnight ago, at least we can rely on one of the finest overtakers in the sport fighting his way back through the field to provide the entertainment this weekend. "It was waiting, waiting, waiting and eventually we got out".
Verstappen, who also spun out in Australia and finished sixth, said he's not going to change the approach that made him, at the age of 17, the youngest driver ever to compete in Formula One.
"We managed to get a few laps in at the end of FP3 and I did enough to feel what the vehicle was like".
Late in making his qualifying sims, the Australian was hampered by traffic but eventually managed to post a best time just 0.405s off his teammate's pace and good enough for third.