The Robins, who are also through to the Challenge Cup quarter-finals, were rewarded for a fast start when Gildart forced his way over for his fourth try of the season.
Sloppy defensive work from Leigh on their own line then allowed skipper Elliot Minchella – in his 100th Super League appearance – to offload in the tackle and give Lewis a walk-in.
Having been firmly under the pump, Leigh enjoyed an encouraging spell, with Bailey Hodgson reaching to dot down, but the Leopards’ riposte was ruled out for a double movement.
The visitors were relieved to see Davies grass Tyrone May’s pass as a length-of-the-field score beckoned, before Leigh spurned chances of their own.
Umyla Hanley broke the line, but chose not to pick out supporting runners before he was tackled, and seconds later, Lachlan Lam spilled the ball metres away from the whitewash.
Rovers absorbed the pressure and immediately stretched their lead, Lewis breaking through two tackles before a superb one-handed offload gave Tanginoa an easy run in.
A strong half was capped when a lightning quick attack down the left saw Joe Burgess chip over the top to give Lewis a clear run under the posts.
Rovers missed a couple of chances to extend their lead after the break, and then seemed happy to contain their visitors and chalked up a third shutout of the season.
But the hosts ended on the offensive, with James Batchelor’s brilliant back-of-the-hand pass teeing up Davies’ fourth score of the season.
