The Greerton wickets were shared around with some outstanding work in the field producing three run-outs.
The Greerton reply got away to a shaky start with Lake Taupō's bowlers having the hosts in early trouble at 16/2.
Taylor Bettelheim went after the opposition bowlers to belt 59 off 39 balls, getting Greerton back on track with the arrival of Brett Hampton at the crease.
Hampton was quickly off the mark, going on to smack an unbeaten 77, with Lee Watkins hitting 23 not out in his side's seven-wicket win.
Mount Maunganui cruised into the Baywide T20 title decider when they removed Bayleys Central Indians for 85 runs and got home with eight wickets to spare.
The Mount Maunganui removal of the Rotorua side's master blaster, Bharat Popli, for eight, and the highest individual score of just 17 runs ensured that the visitors to the Sulphur City faced a modest target for victory.
Former Northern Districts bowler Tony Goodin was the most economical of the Mount attack with three wickets for 12 runs, while Dale Swan and Craig Baldry each took three wickets.
Mount Maunganui openers Ben Musgrave and Peter Drysdale set the platform for victory before Musgrave was dismissed with 27 runs to his name. Drysdale continued on to take his side to the Baywide final with 35 not out.
Baywide T20 semifinals results
Lake Taupō 170/7 (Ray How 60, Michael Mitchell 28, Joe O'Donoghue 21) lost to Greerton 171/3 (Brett Hampton 77, Taylor Bettelheim 59, Lee Watkins 23no; Roger Urbahn 2/35).
Central Indians 85 (Tony Goodin 3/12, Dale Swan 3/15, Craig Baldry 3/18) lost to Mount Maunganui 91/2 (Peter Drysdale 35no, Ben Musgrave 27).
