Murphy kept the pacer brave through parked out fractions of 28.1, 56.4 and 1.26.1 before putting away challenger Likely To Win at the head of the lane to win in 1:56.4.
Roscoes Child rallied for second with Lyndale Royal completing the triactor.
It was the third winner of the night for Murphy who also guided Hollywoodgigolo for owner Scott Dunn, Montague and First Art Down for owner Bruce Wood, Marshfield, PE to victories.
Machinthesand is trained by Hughie Murphy for Noonan Holdings Ltd-Russell & Karen Noonan, Summerside, PE.
Driver Gary Chappell had a hat-trick on the card scoring with Lorne Valley Ricky, trotter Holy Molie Maggie and Gramercy Hanover.
Walter Cheverie recorded a driving double.
Racing returns Monday at Red Shores Summerside at 1pm.
Lee Drake