Australian star Black Caviar landed her 15th Group One success as she landed the Darley TJ Smith Stakes at Randwick.

Winner of the Diamond Jubilee Stakes at Royal Ascot last year, Black Caviar was a little keen in the early stages under regular rider Luke Nolen as Rain Affair went out in front.

Racing in third, Nolen switched wide at the top of the straight and Black Caviar lengthened her stride to pull clear of runner-up Epaulette in effortless fashion.

The Peter Moody-trained mare is now unbeaten in 25 starts and drew a crowd of 25,000 to the Sydney track.

"She's a marvellous horse, what can you say?" Moody told reporters at trackside.

"Twenty-five straight, 15 Group Ones.

"I'm just really proud of her, putting on a great show for Sydney. Sydney hasn't seen her as much as other places.

"Let's hope we see her run again a few more times."