Black Heart Bart has made a remarkable return from retirement to once again make his mark at racing's elite level as a nine-year-old.

His jockey Brad Rawiller has made his own significant comeback, returning to race riding almost five months after suffering injuries including neck fractures in a race fall 12 months ago.

On Saturday, Rawiller and his "old mate" are set for what only months ago seemed a pipe dream, a second crack at Australasia's premier weight-for-age race, the $5 million Cox Plate at The Valley.

"We've both been through the wars, I guess, and we come into the Cox Plate in great form, both of us," Rawiller said.

"And I'm very excited about our chances. I know that we're in the race with a genuine chance."

Black Heart Bart was retired last spring before the former Darren Weir-trained gelding was brought back into work with trainer Lindsey Smith with a view to a spring comeback.

After two unplaced runs over 1400m, Black Heart Bart scored an upset Group One win in the Underwood Stakes (1800m) at Caulfield last month at odds of $101.

He backed it up with a close second to Cape Of Good Hope in the Group One Caulfield Stakes (2000m) last start prompting his connections to pay a $200,000 late entry to run him in Saturday's Cox Plate (2040m) for which he is a $26 chance.

The victory in the Underwood marked a return to the Group One winner's circle for both rider and horse for the first time in more than two-and-a-half years - their sixth Group One win in combination and the 24th of Rawiller's career.

"He's been my old mate for a long time," Rawiller said.

"I actually had to forgo some genuinely good rides early on in his preparation to stick with him because of my loyalty to him and the owners, but at the same time just because of what we've both been through.

"I couldn't not be riding him."

Rawiller said Black Heart Bart's months out of work allowed his once troublesome feet to grow out and paved the way for a racetrack return.

"He was back to being 100 per cent right," Rawiller said.

"And for 12 months to 18 months before that he hadn't been 100 per cent when he was getting to the races.

"He would still run terrifically well and it wasn't like he was not right to be at the races, but he lacked that killer punch.

"Obviously he is a bit older and we've seen in a couple of runs early in his prep over 1400 metres that he hasn't quite got that sharpness that he had previously, but certainly that doesn't stop him being able to get out to a trip and be able to compete against the best."