John Richards had to take time out from Melbourne Cup celebrations to watch Scarlet Billows race at Flemington.

And the mare gave him even more reason to celebrate a "wonderful, wonderful day" when she won the Group Three Hong Kong Jockey Club Stakes to close the Cup day meeting.

Richards is a part-owner of Prince Of Penzance who raced to victory as a $101 chance in the $6.2 million Melbourne Cup.

He also part-owns Scarlet Billows.

Both horses are prepared by Victoria's leading trainer Darren Weir.

"I don't know what's the most exciting. I've got a bigger share in this one than the Prince. But it's just a wonderful, wonderful day," Richards said.

"It's unbelievable really.

"We were up there celebrating about `the Prince', and all along we thought Scarlet was a big chance. And she proved to be a wonderful chance."

Scarlet Billows was ridden by Craig Williams who was thrilled to get a winner on Cup day, even if it wasn't the big one which continues to elude him.

Williams has won two Caulfield Cups, two Cox Plates and a Golden Slipper during his career but is still chasing a Melbourne Cup win and finished 17th on Japanese vistor Hokko Brave.

"Mr and Mrs Richards came down and said `we've already won the Melbourne Cup', and I told them that I didn't so this is my Melbourne Cup," Williams said.

"Credit to Darren Weir and his stable, and a special mention to Michelle Payne - what a great ride in the Melbourne Cup."