In full, Ricciardo's second practice run was 1:11.841 which was closely followed by Belgian-Dutch driver Max Verstappen at +0.194, and Germany's Sebastian Vettel at +0.572.
"We don't head into the weekend as favourites - they are Red Bull and Ferrari", Mercedes team boss Toto Wolff warned ahead of the sport's showcase event. Last year's victor in Monaco was Vettel driving for Ferrari. "If Bernie Ecclestone was still in charge of F1, he would have Sebastian and Lewis at Ferrari next year".
Vettel could do with a boost after winning the first two races and then failing to make it onto the podium in the last three. "We haven't set a fixed date where we want to announce but I can tell you that I don't see a reason why this shouldn't be happening".
"You walk through all the categories like that, then you belong here". Sirotkin recovered from an early mistake at the final corner, which saw his right rear tyre pop off its rim as he hit the barrier and debris strewn across the track.More news: I'm not excited for 'Solo: A Star Wars Story.' What's going on?
Both four-time world champions were also asked by Motorsport.com what advice they would give the 20-year-old, who was sat alongside them during the Wednesday press conference as they spoke.
Ricciardo's homework for the race has included studying on-board footage from Kimi Raikkonen's pole-position lap a year ago, although the highlight of his preparation for F1's iconic race has been the unusual luxury of waking up in his own Monaco apartment bed every morning.
Monaco is home to most of the drivers, including Ricciardo. "It's a place I've always enjoyed going, always enjoyed racing and I've always believed I'll win there". So I'm of the view that it's just a matter of time before until the arm-wrestling. someone wins.
"I also trust the FIA that they would intervene if there was something they didn't like".More news: Houston Rockets owner offers free tickets to Santa Fe High seniors
'We've always had a strong race auto, but Saturday is where we've tended to struggle, at the business end of qualifying.
"I think we'll be pretty decent". "So we have got some things to work on, but we're not completely in the dark; we're in a much better place than we were previous year".
Webber claimed Vettel was afforded preferential treatment by Red Bull's bosses, and although he has now patched up his relationship with the Ferrari driver, Webber rebuffed Vettel's claim that he would be keen to team up with Hamilton.
Renault's Nico Hulkenberg was seventh fastest, ahead of the McLarens of Stoffel Vandoorne and Fernando Alonso, the latter's day compromised slightly by losing most of the first session because of a brake-by-wire issue.More news: LeBron James’s record in elimination games is good but not great