Energywise Ireland Neptune caused an upset by winning 83-69 at recently crowned Domino's MSL National Cup champions Ballincollig in the Domino's Men's Super League on Saturday.
Michael Hayes and Eoin Nelson combined for 46 points in the Cork derby against a Ballincollig side who were missing American forward Latavious Mitchell.
It was back-to-back league losses for Ballincollig, with Ciaran O'Sullivan's side drop to third, after Killester's victory on Saturday and Belfast Star's win over Limerick Celtics on Sunday.
Victory for Ciaran Kiveney's team moves them off the bottom of the table to 10th.
The four teams at the foot of the table each have four wins, however, current 12th-placed side Flexacham KCYMS do have a game in hand.
Belfast Star are now alone at the top of the table after a convincing 89-66 win over Limerick Celtics in UL Arena on Sunday.
Star led by as much as 29 points in the game with a first half that was dominated by Ireland international Rapolas Buivydas.
Buivydas recovered from an injury midweek to start on Sunday and scored 19 of his 21 points in the first two quarters of action.
Roger Wilson scored 22 points in 25 minutes of play to ensure Star went back to Belfast with a record of 11-3.
For Celtics, despite positive games from Ruairi Cronin and Tony Hauser, who combined for 29 points in the defeat, they remain in eighth, occupying the final play-off spot.
Killester are up to second, after they defeated Flexachem KCYMS 75-68 in overtime.
Americans Josh Wilson and Robert Braswell combined for 50 points.
Killorglin managed to build as much as a 13-point advantage, but a strong second half from Killester sent the game to overtime at 67-67.
An 8-1 overtime period gave Killester the victory and saw them move to a 10-4 record alongside Ballincollig, one win behind Belfast Star.
St Vincent’s picked up a vital win in the play-off race, following a 73-68 Dublin derby triumph over Griffith College Éanna.
Vincent’s had four players in double digits - James Phelan, William Thomas, Marcellus Garrick and Adam Lisewski.
The game featured 15 lead changes and a 26-point final quarter from St Vincent's ensured they took home the win by five points.
It puts Vincent's in a strong position for the last home play-off tie spot as they sit at 8-6 alongside both Griffith College Éanna and UCD Marian.
UCD Marian stayed in fourth thanks to a 115-95 road victory at EJ Sligo All-Stars, who slipped down to 11th as a result.
Zachary Hinton had a 33-point game for Marian, along with strong 28-point and 18-point games from Bruce Saintilus and Ronan Byrne.
RJ Etyle-Rock and Jordan Hinds managed to score 51 points between them for Sligo.
UCC Demons ensured they did not fall behind in the battle against relegation, following an 80-75 victory over Garvey's Tralee Warriors.
Despite still missing Tamyrik Fields through suspension, Demons managed to amass a 25-point advantage during the game.
Jordan Washington scored 31 points in 30 minutes of action, along with 13 rebounds for the Cork outfit.
He was flanked by a 22-point game from Tala Fam Thiam.
Demons are now just one win away from the final play-off spot, currently occupied by Limerick Celtics.
The loss for Tralee sees them fall a game behind the three teams above them, sitting in seventh with a 7-6 record.
