Mary's play-off hopes rocked
A shock 34-15 home defeat at the hands of Blackrock College means that last year's beaten finalists St Mary's College are now in danger of missing the play-offs.
The Templeville Road outfit remain in third spot but are now just two points ahead of Young Munster.
The win put Blackrock up to fifth spot in the table. They scored five tries through Alex Dunlop, Alan McGinty, Jan Simon-Byrne (2) and Mark Scott-Lennon, with Robert Sweeney replying with two tries for St Mary's.
Young Munster, meanwhile, moved closer to St Mary's with a 16-3 home success over Shannon. Ray Moloney got the game's only try, with the rest of Young Munster's points coming from two penalties and a conversion from Alan Kingsley, and a drop goal from Willie Staunton.
Old Belvedere remain at the top of the table on points difference, despite being held 16-16 at Anglesea Road by Dolphin. They led for most of the game with tries from Danny Riordan and Eddie Devitt, but Dolphin were never out of it.
They were inspired by Barry Keeshan, who got all 16 points with a try, a conversion and three penalties. Cork Constitution were held to an 11 all draw by bottom team Garryowen.
In Division 1B, Buccaneers are making life very difficult for themselves in the chase for the second automatic promotion spot behind Clontarf. Their 21-15 defeat to Connacht neighbours Galwegians at Crowley Park was their third in a row.
Elsewhere, fourth-placed UL Bohemians went down to a surprise 23-20 home defeat to an improving UCC outfit. Dungannon had a much-needed 21-8 home victory over Bruff, a result which means that the Limerick outfit are now just two points ahead of Galwegians at the bottom of the table.
UCD and Ballynahinch continue to blaze a trail through Division 2.
The Dublin college, the only unbeaten team in the country, hammered Ballymena 40-24, while Ballynahinch won 34-14 in Midleton.
Bective kept their slim hopes alive with a 17-6 win over Old Crescent, while Belfast Harlequins' shock 51-23 loss to Clonakilty did them no favours. That lifted the Corkmen off the bottom and above Old Crescent and Thomond, who lost 58-17 to Trinity.
It's as you were at the top of Division 3 as the leading powers all won. Seapoint lead the way after beating Suttonians 29-13 and Instonians enjoyed a 39-8 win over Banbridge.
Greystones' run continued with a 30-28 win at Highfield, while City of Derry beat Nenagh 23-16 and winless Connemara came within two points of ending their barren run with a 34-32 defeat at Ards. Rainey beat NUIM Barnhall 19-17 and Sunday's Well beat Wanderers 32-26.