Ex-Pilgrim Jordan Burrow had given City a 33rd minute lead at The Jakemans Stadium but Felix levelled a minute before half-time after Dayle Southwell’s shot had been parried by goalkeeper Aidan Grant and Garner swept home the winner with five minutes to play.
In front of 267 spectators, Dennis Greene gave the majority of his squad a run-out ahead of Saturday’s return to Vanarama Conference North action at Harrogate Town.
City’s starting XI featured nine players with first team experience, with 113 Conference appearances and 16 goals between them so far this season, including former United loanee Conner Robinson.