Daniel Ricciardo has opened up on his driver market frustration after failing to secure a move to Mercedes or Ferrari last season.

The highly-rated Ricciardo was heavily linked with the sport's top-two during his final contract year at Red Bull, but eventually signed with Renault after seeing both avenues close off.

Ferrari replaced Kimi Raikkonen with Charles Leclerc, while Mercedes handed Valtteri Bottas a contract extension to partner Lewis Hamilton for a third season.

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Those decisions surprised and disappointed Ricciardo, as he admitted to Sky F1's Natalie Pinkham on her In The Pink Podcast.

"Yes - to answer it bluntly," said the Australian when asked if he was frustrated.

"At the end of the day in the next 12 months I still think, and everybody would say this, that Mercedes and Ferrari are going to be the teams to beat.

"Maybe other teams could take a win here or there, but I think they're still the teams to be with short term."

Though Ricciardo is excited for a fresh start with Renault, who finished fourth - behind Red Bull - in the 2018 standings, he thought he might have had more options available to him higher up the grid.

"Especially after the first six races," he continued. "I won two out of six, so it was Seb [Vettel], Lewis and me who had won two each. At that stage no one else was really touching us.

"I felt like my pull, so to speak, couldn't have been any higher. In a way, I did expect probably more out of that, and at the time I think rightly so."

5:24 Sky F1's Jenson Button is excited about the upcoming 2019 F1 season and thinks that Red Bull's Max Verstappen needs to mount a title challenge. Sky F1's Jenson Button is excited about the upcoming 2019 F1 season and thinks that Red Bull's Max Verstappen needs to mount a title challenge.

Mercedes were 'conservative'

Ricciardo held talks with Mercedes and Ferrari last year, and both teams were seemingly scouring the driver market with Bottas and Raikkonen's futures unclear.

A move to Ferrari may well have been most desirable for Ricciardo due to his Italian heritage - but he "respects and understands" their move to promote Leclerc from their driver academy.

"He's a young up and coming prospect, and maybe that was part of their plan all along, regardless of what my results were and what his results were," he explained.

"With what Ferrari have done, I see it and I respect that because I've seen Red Bull do it, bringing the young kids through the programme. In a way, I think it's about time."

But it's clear Ricciardo felt he should have been in strong contention for the second seat at Mercedes.

Bottas was retained despite failing to challenge Hamilton for the championship, and he didn't win a race in last season's dominant car.

"I guess the Mercedes one is probably a bit of a different situation," he said. "It's a slightly different dynamic with the path they've chosen.

"I guess for them it's more conservative, but I can't argue because it's worked.

"Lewis has won Drivers' Championships and the team has won Constructors' Championships, so in a way they've ticked all the boxes they need."

Ricciardo waited until the summer before confirming he would be leaving Red Bull for Renault.

Listen to 'The return of Daniel Ricciardo' as Sky F1's Natalie Pinkham speaks to the Renault driver on her In the Pink Podcast.