Gardner and Bunjevcevic came through the full 90 minutes unscathed at Highfield Road after recent knee problems ruled them out for a month and 10 weeks respectively.
Both later declared themselves fit enough for Sunday's Worthington Cup Final - nice problems at last on the defensive front for boss Glenn Hoddle.
Back to Barnard's strike though. With 53 minutes on the clock, George Snee and Yannick Kamanan worked an opening down the left flank, Kamanan crossed and Barnard connected on the full with a volley that flew into the top corner from 18 yards - surely the reserve team's goal of the season so far.
And it was no less than Colin Calderwood's young side deserved.
True, the home side could look back on blowing the best chances but our defending got better and better as the game progressed and Mark Hughes, just 18, did a stirling job breaking up play and keeping it simple in midfield.
Coventry's dangerman was Peruvian international Ysrael Zuniga and the snapshot that stung Gavin Kelly's fingers after just three minutes gave an early warning of his potential threat.
Kamanan's 30-yarder had Gary Montgomery scrambling after 15 minutes and Kelly came to the rescue when Marco Brancati and Avun Jephcott carved out the chance of the game after 20 minutes. A one-two cut us open and Brancati had enough time to steady himself but Kelly was out like a flash to smoother his effort from six yards.
Alton Thelwell headed just wide after 23 minutes and was involved in our best move of the first half, switching play superbly to Ciaran Toner who in turn played in Kamanan - this time Montgomery's foot flicked his low shot wide.
Into the second half and Zuniga missed a gilt-edged chance just before we took the lead. This time he exquisitely pulled a high ball out of the air and turned inside Bunjevcevic only to miss the target from eight yards.
A minute later and Barnard's strike put us in the driving seat, not least with the back three of Bunjevcevic, Gardner and Thelwell looking more and more in control.
Coventry were to breach them only once more as Zuniga played in Ivan Guerrero but, with the angle tight, Kelly was always in charge.
A couple of potshots at either end and Barnard's clever lob that grazed the bar were about it for the rest of a bitter night in the Midlands.
Coventry City Reserves: Montgomery, Ford, Pead, Brancati, Cooney, Betts, Magennis, Fowler, Zuniga, Jephcott, Guerrero. Unused subs: Hope, Fahlman, Noon, Cook, Nelson.
Spurs Reserves: Kelly, Consorti, Quilter (Marney, 60), Thelwell, Bunjevcevic, Gardner, Snee (Sutton, 83), Toner, Kamanan, Barnard (Wettner, 82), Hughes. Unused subs: Jalal, Thomas.
All eyes were on Anthony Gardner and Goran Bunjevcevic but Lee Barnard stole the show with a wonder strike as our reserves toppled Coventry City 1-0 on Wednesday night.