Despite his car struggling for pace this year the Australian's wall-hugging exploits saw him post the second-fastest time in the second practice session.

Ferrari's Sebastian Vettel was the fastest on the day, putting in a lap-record one minute12.720 second on the 3.337-kilometre street circuit.

In the hours before his run Ricciardo told Fairfax Media that the upgrades to his car would help Red Bull to be closer to the front in qualifying. He said he had lost no confidence in his own ability to make an impact on the tight confines of Monaco.

"In myself yeah absolutely [I have confidence]," he said. "Obviously it is fair to say in the car that we still have some improvements to make. But you know in terms of confidence in the car, the ability to push the car, I have confidence now, but it's obviously still, when you talk about speed, is it quick enough? We are still obviously not sure.

"This track kind of rewards confidence ... we can probably have a better weekend than expected," Ricciardo said. "It [the upgrades] will bring us closer, I wouldn't expect to be a second off pole here ... We have got a few new parts on the car but it is one of those ones we won't know until we get out on track."

Ricciardo got all the proof he needed once on track with his second-fastest 1:13.207 proving better than Kimi Raikkonen who was another tenth back in third in the second Ferrari, and the Toro Rossos of Daniil Kvyat and Carlos Sainz impressed in fourth and fifth.

Ricciardo's Red Bull teammate Max Verstappen was sixth with 1:13.486.

"We are looking pretty good at the moment,|" Ricciardo told journalists after his run. "We put some good laps together and know where we need to improve so I'm very happy with our position after the first day. We have good downforce here, the rear of the car feels like it is working the best it has so far this year.

"If we can get the tyres warmed up I think we can be pretty close [in qualifying]. I'm pleased with the car's rhythm and set-up which gives me confidence. I don't think we need to do too much to the car set-up wise at the moment, just a couple of small tweaks overnight perhaps."

Last year's race winner Lewis Hamilton, who had topped the morning season ahead of Vettel, failed to improve on that time in the afternoon and trailed Vettel by more than a second in eighth, with teammate Valtteri Bottas 10th.

The result left Hamilton somewhat miffed, although team boss Toto Wolff had indicated a different car set-up for the second session had been to blame.

"We didn't have the greatest day today," Hamilton said. "Practice one was actually really good and we were quickest, but then in second practice we just struggled to extract the grip from the tyres and we were sliding around a lot.

"We've got some work to do ahead of Saturday."

with AAP