Isaak Davies and Dan Griffiths scored the goals in a 2-0 away win which kept Cardiff City top of Professional Under-18 Development League South.
Craig Bellamy, manager of the young Bluebirds, went head-to-head with fellow Welshman Chris Llewellyn, who is in charge of Colchester’s under-18 team.
Merthyr Tydfil-born Llewellyn, aged 39, is a former Wrexham, Neath, Llanelli and West End player who also played for English clubs Norwich, Bristol Rovers and Hartlepool.
The match was played at Florence Park in Essex and Cardiff travelled as PDL leaders, knowing a win would keep them top.
Bellamy’s boys had regained first place thanks to a 2-1 victory against Charlton Athletic with second-half goals from Isaak Davies and Griffiths.
That lifted Cardiff above Ipswich Town in the table, while United are bottom.
This was a seventh successive victory for City against their hosts, a record going back to 2015.
Isaak Davies fired Cardiff ahead after six minutes, calmly finishing, and the same player should have made it 2-0. He was fouled in the penalty area, but his spot kick was saved by goalkeeper Ted Collins.
Rubin Colwill forced the Colchester ‘keeper into a good save from distance, while the U’s had a rare chance when Donnell Thomas headed wide from a set-piece.
Griffiths and Davies combined just before half-time. It was Davies who crossed, but his attacking partner could not turn it home.
Kieron Evans had a chance to increase the lead when he went one-on-one with the keeper, but was denied by Collins.
George Ratcliffe made a sharp save to deny Colchester’s Hutchinson’s close range header, while Ben Margetson went close at the other end when his shot from close in was blocked.
Cardiff’s second goal came after 88 minutes when Jac Davies was sent on from the bench and made an almost immediate impact. It was Griffiths who headed home.
Colchester United: Collins, Wind, Sayer, Cornish, Fouche, Cracknell, Collins, Hasanally, Thomas (Kennedy 83), Hutchinson, Miller, Sims, capt (Stagg 62). Subs not used: Hallett, Patino, Kane.
Cardiff City: George Ratcliffe, Ben Margetson (Trystan Jones 88), Ryan Reynolds, Eli King, Joel Bagan, Sam Bowen (capt), Isaak Davies, Kieron Evans, Dan Griffiths, Rubin Colwill (Jac Davies 87), Ntazana Mayembe. Subs not used: Jordan Duffey (gk), Ryan Kavanagh, Adam Sharif.