Daniel Ricciardo has claimed that Formula 1 powerhouses Mercedes have shown some glaring weaknesses this season and believes that although they are still the toughest of the lot, they have shown they can be beaten.

Mercedes easily swept to their fourth consecutive drivers' and constructors' titles from 2014 to 2017 but have been locked in a much closer battle with Ferrari this season.

Defending champion Lewis Hamilton has also fallen behind Ferrari's Sebastian Vettel in the drivers' championship, largely down to Mercedes' double-retirement in Austria which was then followed by the German's win at Silverstone.

And the recent cracks that seem to be appearing within the garage have been picked up on by Ricciardo.

"They are not as dominant as they have been the last few years," the Red Bull star said, per Autosport.

"That was inevitably going to start to mellow out at some point.

"I still think they are the overall toughest package to beat on the grid but they've shown some signs of weaknesses in some areas.

"Compared to how they've been, yeah they look vulnerable, but still in the big scheme of things they are a strong team and difficult to beat."

Ricciardo, who a short time ago was believed to be holding out for an offer from Mercedes for 2019, has picked up two wins already this season but doubts his Red Bull car will have enough to sustain a serious challenge to the likes of Vettel and Hamilton.

"I still don't think we've got the real pace every weekend to convince ourselves that we can be there [in the title fight]," said Ricciardo.

"I guess Max and myself probably take too many points away from each other - Lewis and Seb are doing all the winning there [at Mercedes and Ferrari].

"We are good enough to win more races. We need to find a little bit to be there on more tracks."

"Hopefully the ones we expect to be quick on, we are. If we come fifth and sixth in Budapest, we're probably going to be pretty p***ed off.

"The odds are against us but I still don't think it's impossible," he added. "There's still too long to go to say it's out."