With both Eoin Reddan and Jonathan Sexton in attendance, St. Mary's College head coach Ciaran Potts paid tribute to the strength in depth of his own half-back pairings.
Former Leinster Academy scrum half Matt D'Arcy and current provincial hopeful Ian McKinley, who had quite an influence on proceedings, were replaced by David Campbell and Gavin Dunne, with the latter's drop goal kick giving Mary's their third home victory in-a-row.
Potts explained: "I suppose not many clubs would have that luxury, but you have to look at filling your key positions.
"Nine and 10 are crucial positions and we are very lucky to have two equally as good nines and equally as good tens that we can rotate, given the conditions, the opposition or how we want to play the game.
"I didn't think we were going to get a penalty from the referee, so we took our chances with a drop goal and got it thank God. We thought we maybe needed to get the ball away from their forwards more, so sent a new nine on with that message and brought Gavin on at 10.
"Gavin is a very consistent kicker with a hugh success rate. We felt if we were going to get one opportunity, we had to make sure we took it."
It was a nail-biting finish at Templeville Road, especially given that McKinley had put a drop goal attempt wide with just over a quarter of an hour remaining, well before the grandstand finish.
"All we wanted to do was keep plugging away and we thought an opportunity would come at some point," added Potts, the former Leinster flanker.
"In fairness to Young Munster, their defence was brilliant and their discipline was very good as well. They didn't really give away an opportunity for a penalty at all, so at that stage you have to take matters into your own hands and go for a drop goal. They are a bit more risky but when you pull them off they are enjoyable as well,"
For Young Munster director of rugby Mike Prendergast, it was the third last-gasp loss suffered by his side this season.
"Very disappointed. I'm gutted to be honest," admitted the ex-Munster scrum half after the game. "It is heartbreaking.
"When you look back at two games before Christmas, (away) against Shannon (18-17) and (at home against) Blackrock (15-14), we lost both games in injury time as well. That is three in injury-time we have lost, but we have Cork Con next week which is an even bigger challenge again."
Prendergast's chages fought back to lead 8-7 and 11-10 at different stages and despite Dunne's drop goal, the Cookies boss was pleased with his squad's overall effort.
"I asked the players to give everything today. It is a very hard place to come and win and to be honest I couldn't have asked for more out of the players.
"Defensively they put their bodies on the line, the organisation (was) excellent coming up against Mary's who are a top class side."
Mary's, who have racked up the points at home this season against Shannon (53-0) and Garryowen (29-6), were held to a solitary try from McKinley, and both Potts and Prendergast were quick to credit the opposition's play.
"I identified before the game that Young Munster would be one of the most difficult teams in the league to beat," said Potts.
"They are very dogged, very disciplined in defence and very hard to break down. You would like to turn possession and pressure into points, but just to get a result out of a game like that, I'm delighted."
Prendergast added: "Mary's have put a lot of points on teams up here, but we are gutted obviously with a drop goal in injury-time. Especially after withstanding a lot of pressure near the end, to lose it by that, it was hard to take.
"We have to go forward. We have another four weeks ahead of us with big games. You have to take a lot of positives out of that."
Looking to the next round of matches, Mary's travel to Shannon who will want to exact revenge for the 53-0 demolition they experienced at Templeville Road in October.
"There will be a bit of a gap between the top three and the chasing pack, but there are still six games left in the season. An awful lot can happen in that time," insisted Potts.
"The next five weeks are going to be very difficult. If you pick up a few injuries and you need results, it is a very awkward position to be in.
"So, it was important to get an early win. It would be important to follow it up with another win next week because you just don't know what will happen."
In contrast, his Young Munster counterpart Prendergast will try to figure out a way to get past Cork Constitution, who were victorious when the two sides met in October.
"We have to take the positives (out of this game). We lost to Con down there at the start of the season. We were losing by six points with two minutes to go and they got a breakaway try.
"The scoreline that day didn't really reflect, it ended 32-19. Guys were gutted after that and today is another hard one to take.
"So all the boys will want to do, after getting a bit of rest after a very physical game, is get back on the pitch and we are looking forward to next Saturday."
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