F1 Austrian Grand Prix: Christian Horner accepts Red Bull still have 'a mountain to climb' in effort to catch Mercedes as Austria returns to the F1 circus

Horner hopes his team can build on their surprise victory for Daniel Ricciardo in Canada two weeks ago

Daniel Ricciardo and Christian Horner celebrate the Canadian Grand Prix victory (Getty Images)

Christian Horner appreciates Red Bull still have a mountain to climb in their bid to catch Mercedes this season ahead of Formula One's return to Austria this weekend.

Daniel Ricciardo's maiden F1 victory last time out in Canada owed as much to Mercedes showing they are far from bulletproof this year as to the Australian's talent behind the wheel.

In taking the chequered flag in Montreal, Ricciardo ended Mercedes' dominant run of six successive wins and five consecutive one-twos to haul himself up to third in the drivers' standings.

Both Nico Rosberg and Lewis Hamilton suffered techncial issues with one of the two energy store units in the car, with the latter forced to retire, allowing Ricciardo to triumph.

Ricciardo, however, still trails championship leader Rosberg by 61 points and second-placed Hamilton by 39, with Red Bull 119 adrift of Mercedes in the constructors' table.

Compared to where Red Bull were at the start of the season when they endured a litany of technical issues with the Renault power unit, the Milton Keynes-based team have come a long way.

Whilst the win was welcome and unexpected, providing a huge tonic to the reigning four-times champions, Horner knows Mercedes' dominance will be difficult to completely break.

"If you think where we were three months ago it is an enormous effort by all the team in Milton Keynes and all the team in Viry (working for Renault)," said Horner.

"Everybody did their bit to get us into a position to win a race and to get two cars on the podium (with Sebastian Vettel third in Canada).

"To get a double podium, to get that first win of the year, was a fantastic performance and great motivation for Renault.

"But let's not beat about the bush - Mercedes were the quickest car, even though they ran into their issues. They were still very, very strong.

"We still have a lot to do as we were 12 or 15 kilometres per hour slower on the straight compared to a Force India or Williams. That is where we need to improve."

Even at this stage in the season, with 12 races remaining, it appears inconceivable anyone other than Rosberg or Hamilton will win the title.

Yet given the strides Red Bull have made, Horner feels his team can continue to push Mercedes.

"You guys (the media) asked at one point if Mercedes could win all the races, and I said theoretically they could but in all probability they wouldn't," said Horner.

"What we have managed to do is keep chipping away, to improve the car, the engine, and in Canada we were there to capitalise on some misfortune for Mercedes.

"But we have to keep pushing and keep closing that gap down because it is still significant."

Whether Red Bull can do that on their home circuit this weekend is another matter, although they are certainly in far better shape to do so now than even a few weeks ago, never mind months.

The Red Bull Ring in the Styrian mountains is owned by the team's billionaire energy drinks magnate Dietrich Mateschitz.

After the circuit fell off the F1 calendar, Mateschitz purchased the then A1-Ring in 2004, beginning a £60million reconstruction four years later.

After an 11-year absence, Mateschitz's dream of seeing his F1 team compete at his circuit will be complete this weekend.

Horner added: "To have a race as Red Bull Racing at the Red Bull Ring, with that inevitably comes a bit of pressure.

"But it will be fantastic to perform in front of what is effectively a home crowd.

"The circuit was sold out in a matter of hours, so it's going to be a huge spectacle that Red Bull put on over the weekend.

"For us as a team, it will again be all about trying to get as much out of the weekend as we can."

PA