Red Bull F1 team has 'overachieved' in 2014 says Christian Horner

After winning a world championship double in each of the previous four F1 seasons, Red Bull lies a distant second in the constructors' championship and has won only two races.

But Horner believes that, given the limitations of Renault's 1.6-litre V6 turbo engine, it has had a strong season.

"Compared to the theoretical handicap we have [with the engine], what we have actually achieved in the first half of the year is remarkable," Horner told AUTOSPORT.

"To have won two races, had front row starts, podiums, is a remarkable achievement, all things considered.

"Obviously, it's not where we are used to being but the team has shown real character to really dig in after a hideous pre-season and fight back.

"So there are an awful lot of positives we can take out of the first half of the year."

Horner added that improvements in the current Renault engine, which he suggests is "65bhp down" on Mercedes will be key to the results Red Bull gets in the second half of the season.

He believes that the recent changes at Renault have made the company more open to making the necessary improvements.

"We have got to make sure that we close that gap in the power stakes further in the second half of the year," said Horner.

"The most encouraging thing is that with the management changes there have been at Renault, they are very open to accepting that there are issues and they need to improve. They are looking at all areas where they can improve.

"With being such new technology, there is still relatively low-hanging fruit that Renault should be able to get their teeth into.

They are not going to close the horsepower deficit overnight, but they can make some inroads into it."