But their lead was shortlived as Rebels fullback Reece Hodge slid through a gap to score out wide five minutes later.
The try of the game around the hour mark pushed the hosts out to a decisive 26-17 lead.
The Rebels secured a turnover near their tryline — five passes and 80m later, wing Andrew Kellaway was over in the corner.
Into the last 10 minutes, Moana Pasifika should have scored a length-of-the-field try of their own but Lincoln McClutchie had the ball knocked loose by Rebels first-five Carter Gordon as he was diving over the tryline.
A 76th-minute try from wing Timoco Tavatavanawai, a persistent threat with ball in hand, gave Moana Pasifika a glimmer of hope.
That chance of snatching a dramatic victory remained with time up after Rebels centre Ray Nu'u was sent off for a high shot on first-five Christian Leali'ifano.
But McClutchie failed to find touch from the resultant penalty, allowing the gleeful Rebels to celebrate their third win of the season.