Red Bull Racing have rubbished suggestions that Sebastian Vettel's Singapore domination was down to the team running illegal traction control.
In the wake of last Sunday's Marina Bay race, allegations surfaced as former F1 team boss Giancarlo Minardi claimed that the Bulls were running a form of traction control.
Horner, though, insists that not only is this not true but that it would be "stupid" for a team to try circumvent the regulations on traction control,
"It's complete rubbish. Any suggestion of traction control is either mischievous on behalf of the others or wishful thinking," the team boss told Sky Sports F1.
"We're running traction control through the ECUs which are supplied by McLaren and approved by the FIA? They fully comply with the rules, it's a standard unit which all the teams use, and any suggestion of traction control is either mischievous on behalf of the others or wishful thinking.
"These things are so tightly controlled that it is impossible. You'd be pretty stupid to run traction control. I can't imagine any team in the pit lane would even entertain it."
The Brit, though, says he gets why the allegation has surfaced but maintains that Vettel's Singapore blitz was based purely on the German's talent.
"The problem is that Sebastian's performance was so dominant that it has inevitably prompted the question of 'how was this possible?'.
"Other teams will be looking inwardly and the easiest conclusion to come to is 'they must be cheating'. But in Singapore, Sebastian drove an incredible race, got the maximum out of the car and was, as a driver, at his peak form.
"What you witnessed was a driver totally at the top of his game and completely in harmony with his car - nothing more, nothing less."