Red Bull team principal Christian Horner said that he didn't regret the team's pit strategy call in the closing laps of the Canadian Grand Prix, and that they had made the only choices available to them in the situation.

If Sebastian Vettel had followed Lewis Hamilton into the pits for a stop on lap 50, Horner pointed out that Vettel would still have ended up stuck behind the Lotus of Romain Grosjean.

"We would have come out behind Grosjean who was going pretty quickly at that stage, so the probability of overtaking him would have been limited," insisted Horner on Sky Sports F1. Instead, the Red Bull's tyres were okay at that point and so they decided to gamble on being able to maintain their existing track position.

"If we'd have pitted before Hamilton the net result would have been the same because we'd have come out behind Grosjean - we might have beaten Perez," he added. "Our only real option ... was to stay out there. But then the tyres really started to get into trouble, so we made a late call to pit and Sebastian managed to get back past Fernando.

"If we'd have stayed out for sure we would have finished much further down," Horner added of their decision to finally admit defeat and call Vettel in during the final half dozen laps after all.

"Maybe, with twenty-twenty vision, starting on the hard tyre a bit further back might have been a better option," he conceded. "We were probably just a little bit too hard on the tyres today to make that one-stop really work."

Despite Horner's confidence that the Red Bull strategists had made all the right calls, their approach still puzzled their counterparts over at McLaren who couldn't see how Red Bull had got into that tricky situation in the first place.

"If you're going to do a one-stop strategy you have to pace yourself accordingly and we just didn't believe it was possible at the pace they had," said former team principal Ron Dennis.

"All the data told us we were doing the right thing [with two-stops] but you never know," added Martin Whitmarsh. "When we came in for that stop we thought it was the right call, and that we could get them if they tried to one stop."

Even so, Ferrari and Red Bull's surprising decision to go another route did cause consternation for a time at McLaren, just in case something had been overlooked in their analysis and planning.

"We were all a little nervous," agreed Dennis.

"There was definitely one lap where Fernando had a pit-stop on Lewis and had he stopped then he would have just raced him to the flag," admitted McLaren's Sporting Director Sam Michael. "But once they didn't take that stop they were committed to making [one stop] work."

And McLaren breathed a sigh of relief to find that their assessment on this occasion had been right, and that two-stopping had indeed been the right call after all.