Red Bull feels F1 tension with Renault pushed Renault forwards

The two sides almost split last year as Red Bull sought an early end to its contract with Renault, and sounded out rivals Mercedes, Ferrari and Honda, only to be rebuffed.

Red Bull was forced to renegotiate its terms for 2016, losing the financial backing of title sponsor Infiniti, as well as rebadging the power unit as TAG Heuer.

Following Red Bull's strong start to this season, the two parties renewed their agreement for a further two years on the morning of Sunday's Monaco Grand Prix.

Horner told Autosport: "There has been a big restructuring within Viry and the right people are now in the right roles.

"They've got some good consultants, they've hired wisely from some of their competitors, so the change from 12 months ago is a culmination of factors that have come together.

"There was a tension, but I'd like to think in some way that tension focused change, and the change that has taken place has been for the best.

"What we are seeing now is the partnership again working well."

Despite the bitterness that ran deep between Red Bull and Renault at one point, Horner has no regrets, with the argument now in the past.

"The most important thing was that there was a reaction, and that reaction was positive," he said.

"So, yes, with the restructuring that has taken place, the consultants that have been brought in, the focus is again there within Viry.

"The guys are doing a very strong job there now, and step by step you can see the progress coming."

Red Bull is now pushing Mercedes hard on track, as it tried to recreate the glory years it enjoyed at the end of the V8 era.

"There has never been a problem with the guys in the field," said Horner.

"The soldiers on the ground have always done a wonderful job for us.

"There was obviously frustration last year at a higher level within the technical management, and the restructuring has addressed that.

"We are now back to where we were a few years ago in terms of a very healthy competitive relationship between the two companies."