Renault progress could tip balance in Mercedes fight, says Horner

After encouraging progress in 2016, many are tipping Red Bull to be Mercedes' main challengers when all-new regulations are unleashed at the start of next season.

But Horner is more cautious about the situation, and thinks much depends on the development Renault can make – with the French car manufacturer preparing an all-new power unit for the upcoming season.

"They [Renault] are working very hard," said Horner. "If they can make the kind of gain that they made last winter, over this winter, then with the stability of the rules, hopefully that [power] convergence will start to happen.

"And, with the chassis hopefully playing a bigger role in the package, it may balance things up slightly.

"But it is all hypothetical as you don't know what everybody else has. All we can do is focus on the best job we can and worry about the others when we see them in Melbourne."

Horner is encouraged, however, by the rate of progress Red Bull made in 2016, having gone into the campaign downplaying its chances and ending it second overall in the constructors' championship.

"We came into the season with very low expectations, and being in the top five in the constructors' looked like it was going to be a challenge.

"So to have come away having finished second in the constructors' championship, third in the drivers' championship, having won two grands prix, pole position in Monte Carlo, 16 podiums, and having had Ricciardo complete every racing lap of the season with 100 percent reliability has been an enormous progression from 12 months ago.

"Despite new regulations coming along for 2017, which obviously are an unknown to everybody, we take an awful lot of benefits and positives out of [2016]."