New South Wales won the toss and sent Western Australia in to bat, with the hosts setting a victory target of 270.
The Blues appeared well placed in their chase at 3-202 on the back of run-a-ball half-centuries from Kurtis Patterson (51) and captain Moises Henriques (72).
But two wickets in as many balls from WA paceman Jhye Richardson helped push the momentum back towards the home side as the Blues lost 3-1.
When former Test opener Ed Cowan was caught in the deep off the bowling of Andrew Tye for 53 in the penultimate over, the Blues were 9-259 and their chase was all but over and the visitors were bowled out with four balls remaining.
Earlier, WA opener Shaun Marsh was the mainstay of the WA innings, with the Test hopeful carrying his bat to score 132 not out and guide his side to 9-269.
Marsh, who hit 17 fours in a disciplined innings, combined with Jonathan Wells (57) for a crucial 119-run stand for the fifth wicket after WA had stumbled to 4-91.