DOLPHIN 31 BLACKROCK COLLEGE 13, Musgrave Park
Scorers: Dolphin: Tries: Dave Ryan 2, Sam Cronin, Robbie Allen; Con: Paul Hurley; Pens: Paul Hurley, Cormac O'Flynn; Drop: Barry Keeshan
Blackrock College: Try: Shane Monahan; Con: Darragh Fitzpatrick; Pens: Darragh Fitzpatrick 2
The Cork side cruised home in the second half at Musgrave Park, with tries from Ireland Club XV captain Sam Cronin and replacement back rower Robbie Allen putting the seal on their fourth win in six league games.
With three sides from Division 1A advancing to the play-offs, this was a crucial victory for Steve Ford's men, who face a trip to arch rivals Cork Constitution in two weeks' time.
Prop Dave Ryan, who featured as a replacement for Munster on Friday night, touched down twice as Dolphin established a 15-10 half-time lead.
Former Ireland Under-20 winger Shane Monahan touched down, with Fitzpatrick's conversion levelling a fast-paced game, but Ryan grabbed his second before the rain began to fall.
Dolphin skipper Barry Keeshan landed a drop goal as the hosts opened the second half well, but Fitzpatrick snapped back with a penalty, two minutes later, as Blackrock trailed 18-13.
However, Dolphin put the game beyond the Dubliners' reach when good handling by Keeshan and centre Danny Barnes led to Cronin crossing and as the forwards took control, Allen crashed over following a 50-metre break by Keeshan.
Young replacement Cormac O'Flynn completed the scoring with a late penalty.