Second-placed Ballymena finished off this first block of four Ulster Bank League games with a hard-fought 22-19 victory over Shannon at Coonagh.
Marcus Horan's hosts recovered well from the concession of a second minute try to strong-running back Rodger McBurney, as prop Tony Cusack crossed in the ninth and 18th minutes to set Division 1B's bottom side on their way to a 12-8 interval advantage.
Loosehead Conor Glynn scored a spectacular third try for Shannon, with Shane Airey's successful conversion extending the lead to 11 points.
However, tries in the 68th and 77th minutes from winger Kieran Joyce and lock Connor Smyth – both converted by Ritchie McMaster – gave the fast-finishing Braidmen the points.
In sunny conditions, another piece of McBurney piece of magic handed Ballymena an early advantage. Out-half McMaster found him in space on the left wing near halfway, and a combination of sidesteps and a change of pace saw McBurney leave the Shannon defence for dead on the way to the try-line.
The groundwork for the try was laid by some powerful carries by Smyth, Matthew Harkness and Oliver Millar, who was making his league debut in the Braidmen's back row.
Indiscipline by Ballymena saw Shannon win a series of penalties close to the line, though, and eventually they drove over for an unconverted try through the influential Cusack.
The young Limerick side repeated the dose towards the end of the opening quarter. Another penalty allowed them to set up position close in, and a well-worked maul put Cusack over to complete his brace. Centre Airey added the extras this time.
McMaster kicked a long range penalty from the 10-metre line to reduce the deficit to 12-8, which is how stayed up to referee Nigel Correll's half-time whistle..
Shannon increased their lead on the resumption when a dropped pass just outside the Ballymena 22 gave the home side possession from the ruck, and prop Glynn gleefully picked up the ball and sprinted in for a try with the visitors' defence nowhere in sight.
That rousing score was converted and with the Shannon leading by 11 points, a much-needed maiden win for Horan's charges was very much on the cards.
The next score would be crucial and tellingly it went to Ballymena as Andy Graham's side upped the intensity and tempo, and kept the ball alive for long periods of play.
The lively McBurney looked to have scored another great try, only for called back for a foot in touch, and Joyce missed out on a try despite seemingly winning the race to a touchdown.
The breakthrough came after a great passage of play in which nearly the whole Ballymena team handled, giving McMaster once again the chance to put McBurney into space. He made the running and a perfectly-timed inside pass found Joyce who finished the move off with a try that McMaster converted. It was now 19-15 and Shannon were within reach.
In the dying minutes of this absorbing contest, a terrific tackle from Ballymena's club captain Willie McKay let Ulster Under-20 captain Adam McBurney in at the breakdown. He won the penalty which was kicked into the corner, and Smyth, with another impressive performance under his belt, drove over from the resulting lineout maul for a try which McMaster converted.
With Ballymena now ahead and time running out, that seemed to be that. In a dramatic late twist, Shannon won a penalty on the Ballymena 10-metre line, but to the great relief of the small travelling contingent, experienced out-half Tadhg Bennett sent his kick to the right and wide.
Referee: Nigel Correll (IRFU)