(Reuters) - American duo Madison Chock and Evan Bates put the finishing touches on their undefeated season with a successful defence of their ice dance title at the world figure skating championships in Montreal on Saturday.

Chock and Bates, who are getting married this year, earned 222.20 points between Friday's rhythm dance and Saturday's free dance to prevail by 2.52 points over Canadians Piper Gilles and Paul Poirier (219.68), last year's bronze medallists.