Max Verstappen says he believes Daniel Ricciardo is indeed benefiting from Renault's upgraded power unit as his Red Bull Racing team-mate set a scintillating pace in second free practice for the Monaco Grand Prix.

The Australian was a mammoth six tenths faster than closest rival Lewis Hamilton in the Mercedes after FP2, with Spanish Grand Prix winner Verstappen within range in fourth place as well, albeit almost a second slower than his team-mate.

Indeed, though Red Bull has been tipped to perform well in Monaco with its well-balanced RB12, it is Ricciardo's rapid FP2 performance that has raised suggestion the new Renault engine upgrade - which Verstappen is not using this weekend - is having an effect.

Though Ricciardo himself has played the gains down, Verstappen expects it is indeed having an effect

"There is a little bit of a difference here," he said. "For sure, especially in Canada it will make a bigger difference, but I have to do the best possible job I can [here].

Regardless of Red Bull's impressive pace out of the box, Verstappen says there are still improvements to come from the RB12 over the course of the weekend.

"[It was] Not too bad," he said. "The feeling was there, I just built it up lap by lap, and we didn't have any crashes, that was the most important thing. We need to work on the car balance, just getting a bit more confident in the car, and from thereon we will see what happens.

"We are not too far off [Mercedes], so we will try to improve our car, because for sure they will do that as well. We will see. For us the most important thing is to work on our car."