Garryowen ensured they will be in pole position going into the Christmas break.
This win also earned them the Shay Deering Trophy, which is contested annually between the clubs in memory of the former international who played with both.
Once again the kicking of outhalf Jamie Gavin was crucial for Garryowen as he landed three penalties and converted two of their three tries which were scored by Conan Doyle, Cian O'Shea and Shane Buckley.
Young Munster 16
A superb try by Dom Lespierre gave Young Munster a huge boost as they inflicted only a second defeat of the campaign on leaders Lansdowne.
Brian Haugh kicked a Young Munster penalty after 17 minutes and Mike Prendergast, despite slipping, landed a drop goal after two early penalties had Lansdowne in control. Haugh kicked his second penalty but two more by Craig Ronaldson had Lansdowne in front 12-9 at the break. He had a fifth five minutes before the end but Lespierre's try, converted by Haugh, was decisive.
UL Bohemian 9
UL Bohemian were denied a bonus point when Harry Fleming scored an intercept try for Dolphin six minutes into stoppage time.
JJ Hanrahan put the hosts in front with a penalty but Brendan Keesham (two penalties and a drop goal) had Dolphin 9-3 in front. Two Ben Martin penalties for UL made it 9-9 with Keesham on target again on 80 minutes; he also converted Fleming's try.
Cork Constitution 23
Shannon are still looking for their first victory after suffering another defeat at Temple Hill.
A try by Conor Desmond and a conversion and two penalties by Johnny Holland had Con 13-0 ahead at the break. Shannon's Rob Guerin bagged a try, conversion and penalty early in the second half. A penalty and a conversion of a Gerry Hurley try by Holland gave the home side a 13-point lead and Guerin failed to convert Cormac O'Donnell's a late try.
A hat-trick of tries from full-back Andy Boyle was crucial in Belfield, as an impressive UCD had 18 points to spare over Dungannon. Jordan Coughlan and Barry Daly also touched down for the Students while Ali Birch and Michael Dunleavy secured some late consolation for Dungannon.
DUBLIN UNIVERSITY 23
Buccaneers ended Dublin University's 100 per cent record thanks to four first half tries. Jack Kelly opened the scoring for the visitors with a try which David Joyce converted but two tries from Kolo Kiripati and one apiece from Alex Hayman and Callum Boland had Buccaneers ahead at half-time by 25-13.
Trinity added a Neil Hanratty try converted by Cathal Marsh and a Marsh penalty in the second half but the home side held out.
Ballymena's quest to avoid relegation received a major boost in Stadbrook, as a blitz of second-half tries gave them their first win of the campaign against fellow strugglers Blackrock College. The Dublin side had a 13-8 advantage at the interval thanks to Peter McCague's five-pointer but tries from Darrell O'Kane, Connor Smyth and Scott Gibson gave Ballymena a much-needed success.
Stuart Olding once again made his presence felt with 16 points in his team's one-sided win over Malone at Deramore Park.
It was a disappointing performance by the Gibson Park team who started the season with three AIL wins and have now lost the last four. They were outclassed up front and never really got into the game.
Quins were 14-3 ahead at the interval but piled on the pressure culminating with a fantastic try from the outhalf.
A powerful Bruff strolled to a huge victory at Ballymacarn Park. Chris Quinn, the former Queen's player, bounded over for a try, four conversions and two penalties in a 19-point haul.
Hinch led 21-3 at half-time but they stepped it up after that to crush Bruff. The visiting forwards were worn down and Hinch's backs were able to run the ball through the demoralised defence.
They had a total of seven tries with Bruff only contributing a first-half Brian Carroll penalty in what was a miserable afternoon at the office.