Her most recent success leading into Saturday's race was in the North Island Challenge Stakes (1400m) at Trentham in May and there was hope in the camp of another win after her fourth to Dez in the Whyte Handicap (1600m) last month.
"She has gone on better tracks like this before and it was a gem of a ride from Ryan [Elliot]," Latta said.
"She can pull very hard and that's been her undoing in a lot of her runs. That's why she goes better on the back-up. She went down in her preliminary relaxed and she was relaxed in the race."
Elliot settled Platinum Command midfield and tracked one of the leading hopes, She's Poppy, into the race from the 600 metres.
Platinum Command surged past She's Poppy to win convincingly by a length, while the lightly raced Dez wound-up late to grab third placing.
For Latta, the win was her third in the Winter Cup, following on from Tuscany Warrior in 2003 and Mikki Street three years later.
Platinum Command is now likely to back up on the last day of the Grand National meeting in the Christchurch Casino Winter Classic (1800m), as she did last year when fourth.
- NZ Racing Desk