Alan McGowan had the last say in a battle of the place-kickers at Ormeau Road on Saturday. The Blackrock outhalf stepped up to kick the winning penalty in injury time and secured a vital win for his team.
Minutes earlier, it had looked as if his Belfast counterpart Paul Handcock had ensured a determined home team a share of the spoils with a sweet drop goal to level the scores.
In a match of few try scoring opportunities, Blackrock looked to have made the breakthrough after 51 minutes through Dave Popplewell but referee Bertie Smith called the play back for crossing.
Blackrock took the game to Belfast in the opening stages and McGowan kicked the first of his five penalties after five minutes only for Handcock to reply with the first of his three after 14 minutes and follow up with the second minutes later.
McGowan equalised and added another simple effort to give his side a 9-6 lead and the outhalves exchanged penalties in the second half to set the scene for the exciting finale.
BELFAST HARLEQUINS: N Malone; J Lowe, S Coulter, S Dick, R Morrow; P Handcock, D Jack; S Best, R Weir, C Boye, K Rablie, D Irwin, G O'Loan, N Best, C McCarey. Replacement: D Scott for Boyd (64 mins).
BLACKROCK: N Turner; P Drew, G Browne, M Jackson, D Johnson; A McGowan, D Popplewell; I McLoughlin, G McEvoy, N Treston, R Casey, L Cullen, D McGettigan, R Rogers, R Murphy. Replacements: A O`Neill for Jackson (63), C Kilroy for Johnson (50), J Ferris for Popplewell (59), A McSweeney (73), T O'Rourke for McEvoy (69).
Referee: B Smith (Munster)
New South Wales coach Bob Dwyer admitted he was "embarrassed" by the below-par performances from his Waratahs after they went down 42-17 to pace-setters and unbeaten Coastal Sharks in Durban.
"It was meant to be a top-of-the-log clash, but I'm afraid we didn't play like a team anywhere near the top of the log," Dwyer said of the Waratahs who with the Sharks had so far been the form teams this year.