Kevin Naiqama and Tommy Makinson both registered hat-tricks as St Helens prevailed 42-26 in an entertaining affair at Hull KR on Sunday.
The Super League leaders were strong favourites ahead of the clash at Craven Park against a side shorn of several first-team members, including captain Joel Tomkins, Mitch Garbutt and Will Dagger.
But the hosts, sitting second from bottom in the table, were 12-0 up inside 12 minutes as Danny Addy and Ryan Shaw went over.
Saints were 18-14 in front by the break, though, as Naiqama's opening two scores sandwiched the first of Makinson's, only for Jimmy Keinhorst's effort to put Rovers back in the lead soon after the interval.
Quickfire tries from Jonny Lomax and Makinson – the latter a surging run from 70 metres – saw the pendulum swing back in Saints' favour but still the home side would not be deterred, Will Oakes reducing the deficit to just two points.
The final quarter of an hour belonged firmly to Saints, though, as Naiqama and Makinson completed their trebles before Regan Grace capped off a pulsating encounter as the leaders picked up their 13th win from 14 matches this season.