The frontman came off the bench to score a late equaliser and salvage a draw with relegation rivals Cowdenbeath on Saturday.
And he picked up where he left off against the Blue Brazil by flicking home a Joe McKee free-kick to open the scoring against Ayr’s second string.
The hosts were struggling to cope with McKee’s set-pieces, and it was another of his free-kicks that picked out Tony Wallace for goal number two on 43 minutes.
Wallace bagged his brace six minutes into the second half when he tapped in Campbell’s unselfish square ball.
Seventeen-year-old central defender Nicky Jamieson added a fourth with a bullet header, and new recruit Jack Smith, who replaced David McNeil at half-time, made it five shortly afterwards. Ayr pulled one back on 68 minutes, but Campbell soon restored the five-goal advantage with a well-taken penalty following a handball.
Campbell completed his treble with a lob seven minutes from time as he continued to make his case for a start against Alloa Athletic this coming weekend.
Morton (4-1-2-1-2): Caraux; Sampayo (Knight, 12), Jamieson, O’Ware, Russell (Fulton, 67); O’Brien; Wallace, McKee; Robertson; Campbell, McNeil (Smith, 46).