He had been on the comeback trail throughout the final round, making a birdie on the 72nd hole just to force a playoff with a scorecard of 71 69 67 71.
McDonald was very strong in the opening two rounds last week, having been the overnight leader on Saturday morning, ultimately finishing with a 67 67 72 72 card.
He was leading by two shots going into moving day, after his started his Friday morning round on the 10th hole and opened with a birdie.
McDonald then picked up two's on the 13th and 17th holes, which was followed by picking up a further two shots on the back nine, at the 4th and 9th holes.
"Today was nothing amazing really. I holed a few putts and I'm just letting everything happen. Just going about my business," McDonald said at the time.
"I'm pretty set on what I'm doing out there, so the game plan won't change too much. Just trying to keep level head and carry on as I am.
"Hopefully the weather doesn't play too much of a part this weekend."
However, conditions were trying at the Pegasus Golf Club course on the Saturday, and McDonald finished with an even-par, watching Lee and Toomey jump up the board as they posted 5-under.
"I'll happily take that score in those conditions out there today. It was really tough out there," McDonald said on the Saturday afternoon.
"I didn't play as well as the first couple of days, but I managed to keep the same calm state of mind.
"I was tested though, I didn't hole quite as many putts which was frustrating, but I'll take that round in those conditions out there, that's for sure.
"I'm pretty happy to have a shot going into tomorrow, I'll just go and play my best golf and we'll see what happens."
Pearce had been tied with McDonald after the first round, and although others played better in the second, Pearce stayed consistent in the changing conditions to finish with a card of 67 71 69 71 to set up a three-way playoff.
