Red Bull Racing has explained the bizarre pit stop blunder that cost Max Verstappen time in the US GP. Verstappen was in the hunt for a podium when he made an unscheduled pit stop on lap 26, catching his crew by surprise. “Max thought he heard a call [to pit] the previous lap and he got himself confused,” said team head Christian Horner. “It’s something totally unusual. He just arrived in the pit lane saying ‘Hi, I’m in the pit lane’. We’re not very good at fitting tyres when we don’t know he’s coming.” Verstappen retired three laps later with a gearbox fault.