Deegan lapping up his first taste of the big time
Leinster Rugby started 2018 as they finished 2017, with a win against an inter-provincial rival.
Munster were accounted for on St Stephen's Day, Connacht on New Year's Day. And for one St Michael's graduate, January 1, 2018 will live long in the memory for all the right reasons.
"Coming into this period of games I knew there might be opportunities. Obviously playing three games in 11 days was always going to test the squad so I had to make sure that I was ready. I missed out on selection for Munster but to get that opportunity against Connacht in a packed RDS and with everything that was at stake, was pretty special all right."
He didn't let the moment pass either, scoring a try in front of family and friends.
"James (Lowe) gave a pretty amazing offload in the build-up and then I just needed to hold my line off Noel (Reid). It was pretty simple from there but the noise was like nothing I've experienced before.
"When I heard it was heading for a sell-out I knew it would be a savage occasion. It was the first time that I've been involved in such a game with that level of interest I suppose. I also had lots of family and friends there and my uncle was over from the States, so it was pretty special to get the try."
The enormity of the game and of the selection is not lost on him. This game was different. Of his nine games since his debut last season, he had crossed swords with the Dragons, for example, on no fewer than four occasions.
Building blocks for the bigger tests. For days like Connacht in the RDS.
"It wasn't a perfect performance but for me, it was as I said my first taste of that level of intensity. The interpros are just different. You hear about them but until you get that nod and you get to run out for one it's hard to describe the tribal nature of them and the energy needed to get through the physicality. It was great."
However, he is now starting to get that nod more and more. Three games off the bench in his debut season last year and now seven games, four as a starter, so far this season - his first as a senior player.
"I am loving it. Obviously when you are an Academy player you are in and around the senior team but the level of involvement can vary, now as a senior player the level of involvement is constant, you are learning every minute of every day from some of the best players in the world. (It) brings your game on hugely.
"It was a nice surprise when the offer of a senior contract came but at the time I didn't have an agent so when Guy (Easterby) asks you into his office for a chat it's a little unnerving because this can go one of two ways!"
He laughs at the moment. You'd imagine that a former U-20 World Player of the Year would be confident in that scenario but not so.
"The quality Leinster have in the back-row is pretty phenomenal and I was still in the Academy and ploughing ahead with my rugby , with my studies in UCD and enjoying it and I didn't really think that it was on the radar but then here you are and that senior contract is being offered ahead of time.
"This is the club that I grew up loving, that I grew up supporting, so it's a pretty special feeling knowing that you'll get the chance to contribute to a really special place."
Deegan is from a family of three with brother Alex lining out with Lansdowne as a prop and sister Charlotte in fifth year in school, with hockey her sporting passion.
While his focus is of course on his rugby there is also the small matter of a commerce degree in UCD to get through. And exam results around the corner. The academic and the rugby all lead him back to one place, St Michael's.
"I had some great years there and loved it. The talent was there but it had to be nurtured in the right way and there are some really good teachers and coaches in Michael's supporting the players and making sure the structures are there to succeed on and off the pitch.
"The culture is excellent so when the players come along the foundation was there I think to make the most of it. The likes Brian O'Meara, Andy Skehan, Emmet McMahon all had a massive influence on all of us."
These were also the same coaches that saw the potential in the 6ft 3in back-rower to mix it up a bit.
"I was always a back-row player, a number eight but then for the Junior Cup year there was an opening in the centre and I was put there. I did finish the season back in the pack but I did play the majority of the year in the centre."
He dismisses the stint in the centre as a once-off but the year in the midfield gave him an appreciation for the finer points.
"The big learning was an appreciation for what the backs do and also see in front of them and knowing what goes on out wide away from the scrum and the line out.
"It's not something that I did a huge amount of but you would still take a lot of that with you and I'd like to think that when I do get the ball in midfield or out wide I have a skill-set that can contribute to what the team is about. Playing at 12 for that season definitely gave me that appreciation."
It is unlikely that Leo Cullen will ask him to pull on the No 12 jersey this Saturday in the RDS against Ulster but interestingly Deegan's formative years were very much influenced by goings on in Ravenhill. "I loved Stephen Ferris so I kept a close eye on his progress with Ulster and Ireland.
"Even now that carry in the Rugby World Cup in 2011 when he literally picks up the Australian scrum-half Will Genia, I can picture it now!
"I liked his physicality, the way he played, man-handling people. He was unlucky with injuries but when he was at the top of his game he was brilliant to watch."
There is no Ferris in this Ulster team but plenty of other threats to keep Deegan & Co up late at night as they look to make it three from three.
"They won't like looking back on their first 40 against Munster but look how they finished the game and the energy and the confidence they will get from that comeback. 17-0 down and to win with a bonus point try, it was unbelievable really. For them they will want to start in the RDS as they finished in Kingspan and it's up to us not to let them."