Bottom club Terenure caused the All-Ireland League upset of the day at Stradbrook this afternoon, toppling league pacesetters Blackrock to claim their first win of season.
Having suffered five consecutive defeats in the league this campaign, few gave 'Nure a chance of taking anything from this tie but the visitors raced into an early 10-0 lead, a Cormac Long try giving them the impetus.
However, Terenure failed to build on that early momentum and Blackrock predictably came back powerfully to lead 15-13 after 60 minutes. But the sin-binning of Blackrock's Malcolm Cuff swung the balance back in Terenure's favour and proved the game's turning point. Richard Governy slotted over the resulting penalty and the visitors hung on to win four valuable points.
Blackrock's defeat allowed Clontarf to take over at the top of Division One, a 34-11 win at home to Lansdowne moving them into pole position while Ballymena are second after their 12-13 win at Dungannon.
In Limerick, champions Shannon again defeated last year's beaten finalists Cork Constitution, after a thrilling finish at Thomond Park.
There was nothing to choose between the sides at the interval, all the points coming via the boots of Shannon's Andrew Thompson and Con's Pat McCarthy.
A long-distance McCarthy penalty edged Con in front shortly after the restart and the two players exchanged penalties again as a listless match appeared to be heading for an away win.
But Shannon injected some life into the contest in the last 10 minutes, debutante Tony Buckley crashing over the line before a late, late Brian Buckley effort - converted by Thompson - made it 21-15 and earned the points for the home side.
AIL Division One
Belfast Harlequins 52 29 UCD
Blackrock College 15 16 Terenure College
Clontarf 34 11 Lansdowne
Co Carlow 10 22 St Mary's College
Dungannon 12 13 Ballymena
Shannon 21 15 Cork Constitution