After exiting the FA Youth Cup in round three, we spoke to Mark Birch.
Speaking to CUTV, he said: "I'm just disappointed to be honest, I think what we took out of the game is key moments of the game, we just lost a little bit of concentration, a little bit of composure but I suppose that's what you get with young players and it's something that we're going to learn from going forward."
Both sides entered the break level, when asked what the message was to the young Blues during this period, Birchy said: "Just be a little bit more patient with the ball and when we can, can we play forward in a smoother way?
"I thought first-half we went forward a little bit too quickly, we tried to force the ball but in the second-half can we just be a little bit more patient, can we draw the opposition onto us and then try to play through them?
"I thought at times we did it quite well but I'd say it's just key moments of the game that cost us in the end."
Argyle took the lead from the penalty spot before Dan Hopper equalised and Lewis Lambert bagged his third on the bounce in the competition.
"Credit to the lads, I'd say we got ourselves in a position with what, four to five minutes to go, that we were quite comfortable and then again it's a key moment.
"I think we lost the middle of the park where we can win a lot of second balls, they play forward early and then we've got nobody to pick up the second ball in the middle of the park.
"We've just been talking to the lads about that in key moments of games, you can play all the good football, you can pass it around but in big moments and big games that's when it's won or lost."
Plymouth then restored parity in the final minute of regular time following a well-struck free-kick from the edge of United's area.
"We gave too many free-kicks away in and around the box, so I think law of averages, one of them is going to hit the target and go in to be fair - the lad slotted it away quite well."
After the Greens regained the lead in extra-time, the Blues thought they'd found their way back once again, but it wasn't to be as the linesman had his flag up for offside. Speaking on this, Mark said: "I couldn't really tell what was going on.
"The ball come across the box pretty quickly and I think the linesman had his flag up quite early as well but I'd say the lads left everything on the pitch.
"I thought from a youth game of football, I think both teams come out with a fair bit of credit, I think both teams give absolutely everything and made a good game of it tonight.
"You really cannot fault the lads tonight but I'd say both teams as well, you've got to give them a bit of credit for the distance they've travelled and I thought it was a good game of youth football."
Touching on the journey in this season competition in further detail, he said: "It's ups and downs and we have to realise it and the lads have quickly realised that, it's the highs and lows of football, you go to Barnsley and you get a great result and everything's high, then you come tonight and we're so close to picking up a result and feeling the lows.
"It's all about development for these lads, it's all about learning and having them winning and losing feelings and taking it forward into the career."
Talking on bright individual performances during the young Blues' run, he added: "Lewis Lambert - he's probably made more of an impact coming off the bench than when he starts, but he'll learn, he's only young and only a first-year.
"Thomas Randall has put in some great performances over the run.
"The under-16s have also come in and done themselves credit but they've got another two years and it stands us in good stead that now we've got some first years coming in next year who've had the ups and downs of Youth Cup football.
As the referee blew for full-time and brought to an end their run, you could sense what the FA Youth Cup meant to the lads.
"They are absolutely gutted in there but they'll dust themselves down, we've got another game on Friday and again it's football, there's always the next game and that probably can't come around quick enough because straight away on Thursday we'll start preparing for that."
