Red Bull have denied that Max Verstappen was deliberately given the preferred race strategy to win last Sunday's Spanish Grand Prix.

While the young Dutchman - who had qualified just behind his teammate on Saturday - was celebrating his first race win on debut for Red Bull, Daniel Ricciardo was openly unhappy.

"I will pull the guys aside who I need to ask what the deal was," the Australian said.

Indeed, Ricciardo was switched to a clearly-inferior three-stop strategy during the race - as was Ferrari's Sebastian Vettel.

Both men were unhappy, unlike Verstappen and Vettel's teammate Kimi Raikkonen who diced until the last metres of the race on the two-stop option.

A strategist from a rival team was quoted by Germany's Auto Motor und Sport as saying: "Red Bull put Ricciardo on the worst possible strategy.

"From the outside, it looked as though the team wanted Verstappen to win, and then Ferrari made the mistake of reacting to Ricciardo's strategy with Vettel."

However, team boss Christian Horner defended Red Bull's decision to put Ricciardo on a three-stop.

"It was clear that Ferrari could only beat us if they tried with three stops, so it made sense to put the better-placed car with Vettel and at that time it was Ricciardo.

"You're always smarter afterwards."

The season continues with the Monaco Grand Prix next weekend.