The right-handed batsman managed 127 at James Oval as the Dragons posted 6-329 from 90 overs.
Hepburn smashed 18 fours in his 244-ball knock, with James Godfrey the other major contributor with 76 n.o.
Kallen Bond finished 47 n.o. in his 100th fixture, with the side now looking to take 10 wickets to complete the win.
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READ NOWAll this after Willetton had been struggling at 3-64, with Hepburn and Godfrey’s 157-run fourth-wicket partnership crucial to getting things back on track.
In Sunday’s Premier Cricket T20 match, Willetton won by 32 runs over Mt Lawley at Breckler Park, inspired by Bond’s 79 from 63 balls.