Central defender Jeff Henderson scored a late winner as Sligo Rovers came from behind to beat Limerick 2-1 at the Showgrounds to maintain their 100% start to the season.
Their fourth straight win since the league season began sees Ian Baraclough's champions five points clear at the top of the table overnight.
Limerick went in front against the run of play on 33 minutes through striker Craig Curran who turned well in the area to drill a shot past Gary Rogers.
In-form Anthony Elding scored for the fourth match running to equalise two minutes into added time at the end of the first half, superbly heading home Alan Keane's cross.
Sligo then won it on 83 minutes when Elding somehow kept the ball in play with a backheel and central defender Henderson swept it home past Barry Ryan. Limerick keeper Ryan was then sent off after the final whistle for confronting referee Rob Rogers.
Gareth Matthews' stunning 89th minute free kick was mere consolation for UCD as they remain pointless at the foot of the table after a 2-1 defeat at home to Dundalk.
College strikers Dinny Corcoran and David McMillan wasted first half chances while Peter Cherrie made good stops from McMillan and Robbie Creevy after the break before Dundalk deservedly struck for the lead on 78 minutes.
Just on the pitch, substitute Tiarnan Mulvenna controlled Richie Towell's ball over the top to turn and delightfully chip Mark McGinley in the UCD goal.
Two minutes later, John Dillon punished sloppy defending from Dane Massey's cross to drill in what proved the winner and move Dundalk up to second in the table.
The game between St. Patrick's Athletic and Bohemians was postponed due to a waterlogged pitch at Richmond Park.