The experience of racing against Black Caviar can no doubt be both thrilling and demoralising.

Jockey Ric McMahon has never ridden against the champion but will do so on Friday night in front of an expected 25,000-strong crowd at Moonee Valley when he reunites with Spirit Of Boom in the Group One William Reid Stakes.

Queensland sprinter Spirit Of Boom is one of six horses entered to take on Black Caviar who is chasing her 24th straight win.

And while McMahon is looking forward to the race, he realises the task at hand.

"She's probably the best racehorse I've seen and probably will ever see. So it's a big thrill that way," McMahon said.

"Obviously it's no good for our winning chances with her in it though.

"But you never know."

McMahon has had success on the Tony Gollan-trained Spirit Of Boom with wins in the Magic Millions Cup and Goldmarket Handicap in Queensland last year.

He has also ridden the sprinter in Brisbane's feature Group One sprints - last year's BTC Cup, Doomben 10,000 and Stradbroke Handicap.

The jockey's association with three-year-old Better Than Ready meant he missed Spirit Of Boom's third in the Oakleigh Plate first-up and Brett Prebble retained the ride for the Newmarket Handicap where the entire finished sixth.

McMahon is looking forward to being back on the Group One-placed sprinter in the William Reid in which Spirit Of Boom is a $21 chance with Black Caviar at odds of $1.04.

"I've had a quick look at the race and on paper it looks like Karuta Queen will probably lead with Black Caviar maybe sitting outside her," McMahon said.

"It would be ideal if we could follow her until before the turn and then see how we go.

"Funny things can happen in racing, but it's very hard to expect to beat her."

The world's best sprinter, Black Caviar pleased Peter Moody in her course proper hit-out at Caulfield on Tuesday morning.

The William Reid has been billed as Black Caviar's final appearance in Melbourne and Moody said he and the owners were still treating the race that way.

But the premier trainer has left the door ajar for the mare to race on next season.

"She's been well looked after, well-managed, patiently guided by her owners," Moody said.

"I think she's going as good as ever.

"Maybe there is another season in her."