Macc's Richard Butcher had deflected in a 26th-minute opener for the lowly visitors, which was cancelled out three minutes later by a Ryan Lowe penalty.
Fit-again Bishop then pounced 11 minutes from time to seal a sixth straight win for third-placed Bury.
"It was a real grind but again, credit to the players," said Knill. "It was a real tough game. They got the first goal from a deflection but there was resilience from the players.
"There was no panic, no desperation, they just thought 'stick to the plan and we'll score'. Macc had three at the back and wanted us to launch it down the pitch so they can head it back. But you've got to move the ball and open up holes, and that typified the winning goal. We opened them up, Stephen Dawson got in behind and played a great ball for Bish."