The 16-year-old from Fermanagh, Northern Ireland was among four 1st year trainees named on the bench by Colin Calderwood - an opportunity that arose due to the under-18s featuring in the fifth round of the FA Youth Cup the following night.
He was the only one to get the nod at Stevenage and a memorable week was completed for the under-16 international when he was named on the bench for Pat Holland's side at Selhurst Park.
Within two minutes of coming on at Broadhall Way, the diminutive midfielder came within an ace of levelling the the match and then tracked back to put in a goal-saving block at the other end.
It was of little surprise that he was still buzzing when he emerged from the dressing room.
"It was brilliant - I really enjoyed it," said Kieran, who confessed to a bit of clock-watching while warming up and yearning for the call to get ready. "I hope to get a bit more action like that because it was brilliant.
"I was hoping I'd get the call up. It got to 80 minutes and he said 'you're coming on'. I was a bit nervous, but on the pitch I was fine.
"I nearly scored, oh, it would have been brilliant. It was a bit behind me and the keeper got out quick.
"It's a pity we didn't win, but the performance wasn't bad and I was happy with my form.
"I'm getting pushed on and I think they are happy with my progress. Hopefully I'll continue to move on and get some games for the under-19s and reserves."
Kieran joined the club on a full-time basis back in the summer and reports that he is thoroughly enjoying the experience - bar a little homesickness from time to time.
"It's been good. I've been playing mostly with the under-17s this season and have enjoyed it. It is my first year, I have settled in well and get on with all the lads.
"Everyone is taking good care of me, so I like it a lot.
"It's a big move, but they do take good care of you here. You do get a bit homesick at times but everyone looks out for you, the coaches are good to you and are understanding if you need a weekend home to see your parents. It's really good."
The under-17s have recorded a mixed bag of results so far this season, but what has become clear is that, on their day, they are capable of pulling out the big results.
"On our day we are good. We beat Arsenal 3-1, we went to second-placed Leicester with a depleted side and beat them 4-3. On our day we can be a match for any team, but we just have to find that consistency.
"We've got a lot of quality individuals in our team and, once we click, we are a team to reckon with."
Colin Calderwood was suitably impressed with the latest addition to his player pool and what caught his eye was the impact Kieron made in such a short space of time.
"Kieron was on the pitch for two minutes and he ended up in the six yard box for a scramble from Etherington's cross. He was then fighting for the ball at the other end and put in a vital block.
"I think you could see that he has an eye to getting in the box and an eye to look after the ball when he has it.
"For the amount of time he was on the pitch I have five or six recollections in my mind of him doing something positive. It is a good sign."
Kieran McKenna, on Wednesday evening, became the first of this season's under-17 intake to sample reserve team football when he entered play the final eight minutes of the match against Coventry City.