The Ellis Winsloe-trained 6yr-old made it career win No6 with a front-running win for rider Terry Moseley.
Nomen Ludi dug deep in the straight to hold off runner-up Galway Garry by a nose.
Rider Kylie Williams brought up her 700th career win in the saddle in New Zealand with a winning double.
Williams rode Morweka to win Saturday's open sprint and Queen Jetsun to win in rating 65 company.
Several of the beaten runners in the event put in good first-up runs before their major spring targets.
Kiwi Ida rallied well for second and Prince Oz ran on well from the rear to take third.
Matamata filly Woodcote Lass showed she was on target for the Riccarton spring features when winning Saturday's 1000m event for 3yr-olds.
The Stephen Autridge-trained galloper held out last season's leading South Island 2yr-old, Miss Federer, by half a length.