Monaco GP: Ricciardo thinks Red Bull can challenge Mercedes for win

Although the opening day was affected by a rain shower that limited running in the afternoon, the fact that he and team-mate Sebastian Vettel were close to Formula 1's pace-setter was encouraging.

"The morning went well," said the Australian. "It is still early, but we are there or thereabouts with them [Mercedes].

"With a few little tweaks over the next 24 hours and for Saturday, if we get it the way we want, we will give them a run."

Red Bull had headed into the weekend hopeful that the street circuit would offer it its best opportunity yet to beat Mercedes.

And judging by the relative performance against its main rival, Ricciardo said that there had been no indication yet to dampen its hopes.

"I think if it [beating Mercedes] is going to be anywhere, this is the place for it," he said.

"They don't seem to have a sector at the moment that is blowing everyone away. It is still early days but if we get it all together we can challenge them on Saturday."

Vettel was slightly more cautious, even though he reckoned the progress made in Spain was evident by early running in Monaco.

"They [Mercedes] are the favourites," explained the world champion. "They were very quick this morning and we see that come Saturday they are able to pick up their pace, so we will try to do the same.

"We potentially are a little bit closer here, but at the moment it is all guessing.

"I think the big advantage on this track is that there are not that many straights, but we have to wait and see."

MERCEDES STILL BULLISH

While Ricciardo was optimistic about challenging Mercedes, championship leader Lewis Hamilton said his squad had plenty of cause to be bullish about staying ahead.

"It was great," said Hamilton. "Really surprised things started off so well. Incredible car and just taking it one step at a time.

"The track is amazing as well. The car is behaving a lot better than last year for me."

His team-mate Nico Rosberg was only 20th in second practice, but said he had just held back in the drying conditions.

"It was just impossible for me to learn much out there because the track wasn't quite the same as this morning," he said.

"I didn't want to put it off when the tyres were a bit cold and the track too. "