Buccaneers staged a gutsy second half fight-back to draw 20-all with Dublin University at Dubarry Park and jump one place up to fourth in the Division 1B table.
Trinity were on course for their fourth straight victory when leading 17-5 at the break, with flanker Brian du Toit touching down for the third time in recent weeks and winger Killian O'Leary also nabbing a try.
However, the Pirates recovered well and bossed most of the second half. Tries from Garreth Halligan and Jacob Walshe were added to by fellow front rower Shane Delahunt, the recent Connacht debutant.
Ross Keller, another influential reserve for Buccs, kicked a conversion and penalty with Trinity's number 10 Jack McDermott landing a last-gasp penalty for a share of the spoils.
Buccs went on an all-out attack from the start but Alan Gaughan missed a second minute penalty, while Kolo Kiripati threw a wild offload when the midlanders had a two-man overlap four minutes later.
Stephen McVeigh then blocked down an attempted clearance by McDermott but the visitors' out-half was fortunate that the ball rebounded to him on the ground.
It took Trinity 14 minutes to get into the home half and then Sebastian Fromm carved a huge gap in the Pirates cover. Several quick hands later and du Toit was touching down for a try which McDermott converted.
While Buccs were still reeling from this setback, they leaked a second try just three minutes later when O'Leary surged in on the left. McDermott added a fine conversion for a 14-0 lead against the earlier run of play as Tony Smeeth's young guns now hit a purple patch.
The students had their tails up as the sails came off the Pirates vessel and some fine mauling added further to home discomfort with Buccs flanker Rory Moloney picking up a yellow card after 23 minutes.
McDermott stroked over the resulting penalty and the Athlone side's capitulation looked possible especially when out-half Gaughan was injured shortly afterwards.
Trinity were very slick and impressive at this stage but Alex Hayman did very well to deny them a try by winning the chase back to tidy up from a dangerous kick ahead.
Buccs duly regrouped in the closing stages of the half, Callum Boland kicking a penalty to touch on the right just before half-time to regain their momentum. Hooker Halligan was brave in forcing his way in for an unconverted try in the final move to make it 17-5 at the interval.
Buccs came racing out of the blocks on the restart and a last-gasp hand trip denied Daniel Qualter's thundering break its due reward before Saba Meunargia was stopped just short of the whitewash.
As Buccaneers piled on the pressure, a Trinity player appeared to deliberately knock the ball forward as the Pirates drove forward close to the opposition line. However, referee Sean Gallagher penalised the hosts for a knock-on. This decision, one of several debatable ones to go against the Pirates, merely delayed their second try.
Audi Athlone man-of-the-match Luke Satchwell and Kiripati powered Buccs forward and prop Walshe (pictured below) surged over the line for a 49th minute try which Keller converted via the crossbar to reduce the arrears to 17-12.
The pressure was now relentless on the visitors and replacement Tom Ryan was sin-binned for persistent infringing just after the hour mark. Keller thumped over the resultant penalty to leave Buccs just two points adrift.
Seven minutes from time, Buccaneers worked an absolutely magnificent maul from 26 metres with Delahunt applying the finishing touch for a try on the left. Keller's conversion attempt was only marginally wide at 20-17.
Dublin University responded but surprisingly opted for touch with a late penalty which the in-form McDermott may well have converted. But still more drama and controversy followed in a frantic finish.
Trinity forced another penalty when Keller's attempted block down was deemed a deliberate knock-on and the replacement out-half was yellow carded.
McDermott held his nerve to steer over the penalty to ensure a share of the spoils with the last kick of a lively tussle. Overall, a draw was perhaps a fitting outcome and both teams moved up the league table as a result with Buccs now fourth, one place ahead of the students.
Referee: Sean Gallagher (IRFU)