Sanasar settled in behind New Plymouth's Just The Tip (Hayden Tinsley) on the first run past the post as the six-horse field settled into a steady pace, while Foxton's Skybird (Masa Tanaka) hugged the rail as it saw off the challenge of Whanganui's Cheese Maker (Danielle Hirini), who is trained by Kevin Myers on behalf of Marton's O'Leary brothers.
Moseley said he was happy to draft along behind Tinsley until the final turn.
"He'd jumped well, Michelle [Northcott, assistant trainer] said 'don't jump him too hard'.
"We just slid outside [Tinsley], soon as he came outside the tempo went up. I didn't know I'd win, but I thought I'd take some beating."
Sanasar had the momentum and won by two lengths in 2m 16.56s, with Just The Tip holding second.
The Dan O'Leary-trained horse Red King (Miranda Dravitzki) got up for third on a pretty good day for the O'Leary family as Who Shot Thebarman had also finished third at the Group 3 Sky High Stakes (2000m) at Rosehill Gardens.
A solid crowd watched the Saturday races with the corporate marquee humming, as Waverley Racing Club's Sam Lennox thanked the punters during the Cup presentation.
"It's a great crowd, and this is our day and it's got to have the people out here in the sun."