Whitehill settled quickly and Daryl Healy saw an effort saved by the keeper before Connor Brydon hit the post following up a parried shot from Michael Osborne.
On 11 minutes they opened the scoring when Osborne played a ball behind the Preston left back for Healy who beat the onrushing goal keeper to slot into the empty net.
With 38 minutes played Keane had a great sight of goal but blasted high over the bar from 15 yards.
Two minutes before half time Bryan Young was called into action and did well to close down Jason Young cutting in on the angle one on one.
Shortly before the hour mark the Welfare doubled their lead when Steven Manson was scythed on the edge of the box and Osborne placed a side footed effort into the bottom right hand corner.
Preston sought a way back into the game but as they pushed players forward Osborne scored again to make it 3-0 from 10 yards.
With 12 minutes left Preston substitute Jamie Cochrane sprung the offside trap to pull a goal back.
Any doubt over the result was ended on 81 minutes when Brydon rounded the visiting goalkeeper before squaring for John-Ross Kerr to tap in.
Whitehill: Young, Robertson, Kidd, McDiarmid, Dodds, Osborne, Manson, Brydon, Healy, Chalmers, Kerr. Subs: McAuley, Baillie, McCabe, Jardine.