First-half goals from Wes Harding and Matt Green saw Richard Beale’s charges overcome the non-leaguers and claim the silverware.
Nuneaton boss Liam Daish’s return to his former stomping ground was ultimately unsuccessful but the travelling fans did at least have a goal to cheer when Joshua Rees pulled one back.
In fact the relegated Conference Premier team made a real fist of it after the break and had their illustrious opponents on the ropes during the closing stages but the hosts held out.
Nikola Zigic made his final appearance on home soil and played his part in the success with an assist for Harding’s opener during a hard-working performance from the big Serbian.
Nuneaton started well and only the woodwork prevented them from taking a fifth minute lead. Jannai Gordon took advantage of a mistake from Mitch Hancox to unleash a shot from 15 yards which was deflected onto the angle of bar and post by the head of Harding.
Six minutes later and Blues twice went close to opening the scoring in the space of 60 seconds. Dom Bernard’s delightfully chipped ball into the box found Green unmarked just five yards out but his header was terrifically turned over by Nuneaton’s on-loan keeper Max Crocombe.
Moments later it was Bernard himself that cracked in a goalbound shot inside a crowded penalty area but Gareth Dean was in the right place to block.
Beale’s side were not be denied though and edged ahead on 13 minutes. Zigic played a pivotal role in the goal as he headed a left wing corner back across the six-yard box and Harding nodded the ball in from almost on the line.
An impressive solo run from Ryan Smith then took the Nuneaton midfielder from the halfway line to the edge of the Blues box. But the ex-Coventry City scholar’s finish didn’t match his approach play as he sliced his shot well wide of the target.
Theo Streete did well to block Green’s low drive from the edge of the box and a few minutes later the former Rotherham United man also prevented Josh Cogley from firing home after a fantastic jinking run by the Blues right-back.
However, in between those two chances Blues had already doubled their lead. Cogley was the creator with a terrific diagonal ball that found Green just five yards out and the striker glanced his header beyond Crocombe.
It could have been a quick-fire double for the ex-Mansfield man as he picked up the ball on the edge of the area but his side-footed effort was saved by the legs of Crocombe.
Zigic could have got his name on the scoresheet just before the break from Hancox’s overlapping run and cross but the ball bounced over the big Serbian’s foot inside the six-yard box.
The half finished with a rare dangerous moment created by Boro. Andy Brown tried his luck with an effort from 20 yards that curled in towards Nick Townsend’s goal but not enough to trouble the Blues custodian.
Blues made one change at the break with new St. Andrew’s professional George O’Neill replacing Kamal Guthmy.
Reece Brown missed a great one-on-one chance to extend Blues’ lead when he latched onto Zigic’s pass but the U21s’ top scorer was denied another goal to his tally as Crocombe saved again with his legs.
It proved costly as on 58 minutes Nuneaton reduced the deficit. An impressive move ended with Rees volleying home in emphatic fashion from ten yards giving Townsend no chance.
Boosted by that goal the non-leaguers went in search of an equaliser and could have grabbed one had Brown’s shot from the edge of the area flown either side of Townsend rather than straight at him.
The Blues keeper also had to be on his toes to collect Gordon’s fizzing long-range effort as Daish’s men continued to press.
At the other end O’Neill could have made the tie safe on 67 minutes but the substitute’s smart chip was clawed away by the fingertips of Crocombe.
Nuneaton won a succession of corners which came to nothing but did come close from open play. Ree’s cross was met by the head of Brown but his effort dropped narrowly over the bar.
The Blues fans nearly got the finish to the night they wanted when Brown’s cross found Zigic at the far post. The big man’s header was arrowing towards the bottom corner until Dean got in the way to make a goal-saving block.
Blues survived more late Nuneaton pressure to seal the win and Townsend and Hancox jointly lifted the trophy as the U21s’ season ended in triumph.
Blues: Nick Townsend; Josh Cogley, Mitch Hancox (c), Wes Harding, Dom Bernard; Viv Solomon-Otabor (Perry Cotton 78), Charlie Cooper, Reece Brown, Kamal Guthmy (George O'Neill h/t) ; Nikola Zigic, Matt Green.
Subs (not used): Nat Kelly, Jake Weaver, Kyle McFarlane.