The Young Terrors suffered a disappointing afternoon at Whitton Park as they fell to a 4-2 defeat at the hands of Celtic.
After a poor start, comeback goals from Kai Fotheringham and Archie Meekison had United just a goal behind at the interval. But a quick fourth at the start of the second half for the visitors was too much to overcome.
The Young Terrors did go close after just two minutes through Shaun Brown but he flashed his shot across the face of goal and wide of the far post.
By the end of the opening ten minutes Celtic were in front thanks to Ben Wylie. The young striker got a stroke of good fortune when his effort took a wicked deflection past Reece Beveridge, who was left flat-footed.
United went close to equalising in the 19th minute when Layton Bisland tried to pick out Fin Malcolm with a great delivery into Celtic's box, but the 16-year-old couldn't make the connection to knock the ball into the back of the net.
Three minutes later the visitor's would double their advantage when Adam Montgomery was picked out with a defence-splitting pass before slotting a low finish into the bottom corner.
The Young Terrors would respond instantly, however, with a quick counter-attack as Malcolm sent Fotheringham charging through on goal. The 16-year-old kept his composure to finish the move and get United back in the game.
It wouldn't take long for Celtic to re-establish their lead as in the 28th minute Wylie added his second of the match with a dinked effort from just inside the box.
Beveridge was called into action in the 40th minute when he tipped Barry Hepburn's 30-yard effort over the bar.
United would go in at half-time just a goal down after they were awarded a penalty when the referee deemed the ball to be handled inside the area. Meekison stepped up and kept his nerve as he sent the keeper the wrong way.
The Young Terrors would have been hopeful of levelling the match heading into the second half, but those hopes were dashed inside 60 seconds of the restart when Owen Moffat tapped home after the ball fell directly into his path.
As the wore on, United had the better of the chances. The first came on the hour mark when the ball fell to Fotheringham after ricocheting inside the box, but his effort deflected off a Tangerine shirt and flew wide.
Malcolm then went close four minutes from time when he eased past two Celtic bodies to drive into the box, but he pulled his shot into the side netting and the visitors saw out the win.
"First half we were too passive in midfield. In key areas of the pitch we didn't want to make contact and that's going to cause you a problem and allow their key players to get on the ball," said Head Professional Performance Coach Adam Asghar.
"There was naivety in boys stepping out too early to press and then not making contact, being too nice and giving us a mountain to climb in what should have been a competitive and even first half.
"With 20 minutes to go we decide to start playing, being aggressive and creating chances but by that time it is probably too far gone.
"You can't expect to turn up against a team like Celtic and play for 20 minutes and expect a result."
Full reactions from Asghar and new Academy signing Sam Lovie are available now.
Next up for the Young Terrors is a trip to St Mirren on March 13th.
Team: Beveridge, Bisland, Lovie, Fraser, Neilson (Caves 46'), Hutchinson, Brown, Smith, Malcolm, Meekison (Watson 57') and Fotheringham (Walker 74').
Subs: McCabe, Robson, Cooney and Naglik