The Sky Blues suffered defeat in the Second Round in the Birmingham Senior Cup away at Nuneaton Borough.
The hosts took the lead and it was former City man Devon Kelly-Evans who found the back of the net when he found the bottom corner from inside of the box after just five minutes.
Billson was called into action a few minutes later after a shot from distance by Callum Powell forced the ‘keeper into a low stop.
City’s first opportunity on goal was through midfielder Josh Eccles after he was teed up by Bapaga on the edge of the area, but Tony Breeden was down well to make the save.
Bapaga continued to cause the hosts problems and after Charlie Wakefield beat his man, he found Bapaga who’s first time effort forced Breeden into another stop down low to his right.
Kelly-Evans was looking to be the hosts best outlet and he ran towards goal and picked out Jamie Towers, but his shot lacked conviction and was comfortable for Billson.
Nuneaton looked for goal from distance once more when Powell’s powerful drive deflected off Morgan Williams and went just wide of the goal.
After the break, the hosts doubled their lead and it was substitute Owen Wassall who’s first time effort from inside of the box found the bottom corner.
Billson made a decent stop on the hour mark as head to be on alert to stop Towers’ turn and effort on the edge of the area.
City almost pulled one back through David Bremang as he beat the offside trap and looked to lift it over Breeden, but the ‘keeper read the chip and saved.
The striker had another chance moments later, but after Josh Eccles picked out the striker, he headed wide from inside the box.
Up the other end, Billson produced a fine save to deny a Ryan Edmunds volley from outside of the area, with the ‘keeper tipping the ball over the bar.
Borough did find a third goal and it was Borough captain Joel Kettle who headed home from a corner to extend the hosts lead.
City almost found the back of the net late on when Eccles played the ball out wide to Bapaga, but his shot went over the bar, in what would prove to be the last action of the game.
Yellows: Josh Eccles 69’
Sky Blues Xl: Tom Billson, Tennai Watson, Declan Drysdale, Morgan Williams ©, Joe Newton, Jamie Allen (61’ Jack Burroughs), Josh Eccles, Will Bapaga, Charlie Wakefield, Gervane Kastaneer (64’ Jonny Ngandu), David Bremang.
Unused Subs: Cian Tyler, George Burroughs, Joe Nightingale.
Nuneaton Borough Xl: Tony Breeden, Devon Kelly-Evans, Nigel Julien, Nathan Parker, Joel Kettle (C), Jack Byrne, Callum Powell, Isaiah Osbourne, Jamie Towers, Ryan Edmunds, Akeal Rehman (46’ Owen Wassall).
Unused Subs: Tyrell Belford, Harry Jackson.