Jack Marriott scored a hat-trick as Peterborough made it maximum points from their opening two League One matches with an impressive 4-1 victory at Bristol Rovers.Posh took a sixth-minute lead when Ryan Sweeney failed to clear a cross from Gwion Edwards and Marriott pounced to fire home from close range.A Junior Morais pass set up strike partner Marriott to score his second in the 55th minute and Steven Taylor forced the ball over the line for a third with 12 minutes remaining after Jack Baldwin had headed on a left-wing corner.Rovers grabbed a consolation five minutes from time when substitute Rory Gaffney headed home a Lee Brown cross at the far post.But Marriott completed his treble in time added on, tapping in a low left-wing cross from substitute Andrew Hughes.Posh had the better of the first half but survived a scare just before the break when Billy Bodin's left-footed drive from the edge of the box crashed against the crossbar.Rovers also hit the woodwork in the second half through a looping header from substitute Ollie Clarke.