Connacht Academy player Callum Boland struck for the decisive try in Buccaneers’ win over Division 1B leaders Clontarf in Athlone on Saturday.
Clontarf's advantage at the top of the table has now been cut to just two points as the league action hots up during a busy February period.
The defeat marked 'Tarf's first loss in five Division 1B and gave Buccaneers a shot in the arm as there now is a 10-point gap between themselves and third-placed Lansdowne.
Connacht's Aidan Wynne started in midfield for Buccaneers in the only change from their win over Bruff last time out. Clontarf, who beat Buccs 25-15 in October, lined out with Martin Dufficy at out-half and Noel Reid at full-back.
Buccs forced the issue early on and scrum half Adam Kennedy opened the scoring in the 10th minute, slotting a penalty after two earlier misses.
Kennedy's half-back partner, Jack Carty, kicked well behind a solid Buccs pack and went on to win the man-of-the-match award for a controlled display.
Scoring chances were few and far between in the first half, and the hosts took a 3-0 lead into the break. Reid missed penalty attempts after 25 and 40 minutes, one going wide and the other falling short of the posts.
Clontarf got on top shortly before half-time, visiting the Buccs' 22 for the first time, and Reid drew them level just after the restart. The Ireland Under-20 international punished a scrum infringement.
Kennedy replied with a 50th minute kick, after Carty pushed a drop goal shot wide while Buccs had a penalty advantage.
Referee Alan Rogan was a busy man as the penalties were coming thick and fast. Two more shots at the posts were missed by Reid, who moved to out-half following the introduction of the experienced Daragh O'Shea.
Carty lacked support when he made one of the few line breaks in this closely-fought encounter which was full of hard hits and tactical play.
A missed penalty from Reid was followed by a yellow card for Buccs lock Clifford Richardson for peristent offside, and the resulting penalty was nailed this time by Reid.
6-6 on the scoreboard, the playing numbers were then evened up with Clontarf number 8 Martin Garvey seeing yellow for obstructing teenager Carty as he chased his own kick.
Buccs' best spell followed, with backs and forwards combining in attack. They finally breached the north Dubliners' defence in the 78th minute, with Shane Monahan's cross-field kick teeing up fellow winger Callum Boland for the match-winning try.
Kennedy missed the conversion from the right touchline, but it was not needed as Hendre Marnitz's men made it five league wins on the trot.
Referee: Alan Rogan (IRFU)