There was no joy for the United youth team at Glenesk on Saturday morning in what was overall a disappointing display.
Indeed, even the late flourish that brought some good scoring opportunities could not hide a poor performance, particularly in the first half when the youngsters hardly ever threatened.
Apart from a couple of wayward David Gray free-kicks, the only real chance of the opening period came a minute before the break when David Goodwillie forced his way through on goal but fired wide.
By then they trailed to a 21st minute goal when Jim O'Brien waltzed past two defenders as well as keeper John Gibson, who slipped as he came out, to slot the ball into the empty net.
Five minutes into the second half, Celtic increased their lead when Kieran McAleenan brought down Paul McGowan and Marc Millar scored from the spot for a second time after the referee ordered a re-take.
Even though Celtic were reduced to ten men a minute later when Charles Grant was red-carded for a second yellow card offence, McGowan would have made it three but for a good save by Gibson.
Things were evened up numerically ten minutes into an explosive start to the second half with United defender Gregg Burnett getting a straight red for a late challenge.
It was in the latter stages that United finally made an impact as an attacking force with substitute Ryan McCord heading against the post after 77 minutes.
With the visiting keeper Scott Fox making good saves from Goodwillie, McCord, and Andreoni in addition to Ryan McCafferty clearing off the line from Goodwillie, the home side's flourish finish could easily have earned them a point they might just have deserved on that late charge alone.
Dundee United: Gibson, Flynn, McAleenan, Burnett, Donnelly, Pope, Russell (O'Hara 75), Andreoni, Feeney, Goodwillie, Gray (McCord 62). Subs not used: Jeffrey, McMeechan.
Celtic: Fox, Caddis, Richardson, Grant, Craib, McCafferty, Millar, Ferry, O'Brien (Anderson 89), McGowan (Carey 83), Lensky (McGroush 80). Subs not used: Skinner, Staunton.