Listen to this article Verstappen was set to finish second at Albert Park on Sunday, only to slow with 20 laps to go and park up at the side of the track at Turn 1 to retire from the race. It marked Verstappen’s second DNF in three races, meaning he is already 46 points behind early championship leader Charles Leclerc, who scored a dominant win for Ferrari in Melbourne. Verstappen said after the race it was “unacceptable” to be struggling so much with reliability and that he was “already miles behind” in the battle to defend his championship. Speaking in the Albert Park paddock after the Red Bull team debrief, team principal Horner confirmed a fuel system issue was to blame for Verstappen’s retirement. “Obviously it’s very frustrating to have a DNF on Max’s car,” Horner said. “It looks like a fuel system issue, external to the tank, that has c …