Record-breaking jockey James McDonald has lavished praise on Via Sistina after she confirmed her billing as Australia's best racehorse with a dominant victory in the $3 million Champions Stakes.

McDonald barely had to lift a finger aboard the Chris Waller-trained Via Sistina at Flemington on Saturday, comfortably steering the short-priced favourite home in the 2000-metre Group 1 test.

The imported mare won by a widening margin of almost three lengths from last Saturday's Empire Rose Stakes winner Atishu and last year's Caulfield and Melbourne Cup winner Without A Fight.

"That was awesome. Everything just went beautifully to plan," McDonald said.

"I had the horse to really give me a smooth ride - 600 metres, 400 metres, it was just like changing gears and she just went."

The result helped McDonald set a new mark with 11 wins over the four days of the Melbourne Cup carnival, breaking his own record when he rode Pisanello to victory in race nine on Saturday.

The tally included four Group 1 triumphs - two each on Derby and Champions days.

"It means a lot. It should have been probably 15, butchered four, got 11 right," McDonald said.

"So it's just the way it is, but it's a privilege, it's an honour to ride here, and especially this week.

"Great atmosphere, the crowd makes it so much fun to ride here, and these four days are very, very special.

"The colour, the vibe, everything about it, and the special horses, like we just witnessed a superstar (Via Sistina).

"I'm still coming to terms with what happened there, but very special week."

The Yulong Investments-owned Via Sistina has emerged as Australia's best racehorse amid a run of four Group 1 wins in five starts this spring.

The commanding Cox Plate and Champions Stakes showings came after Via Sistina threw McDonald during trackwork days before Australasia's weight-for-age championship, in an incident that initially cast doubt over her immediate racing future.

But the seven-year-old mare has since gone on to become the star of the spring carnival in a response that McDonald said speaks volumes about her ability and demeanour.

"It's been an enjoyable ride. How you compare it (to the Cox Plate run) ... felt pretty good today," McDonald said.

"She was never in doubt. The nice building pace suited her.

"She just keeps going to a new level. She enjoys her work ... she loves it, and she puts that into her race as well.

"She's very good and today was an absolute joy and pleasure and I had so much fun on her. Her performance speaks for itself."

Via Sistina was installed as Melbourne Cup favourite after the stunning Cox Plate success, secured by a record-equalling eight lengths in a time that broke super mare Winx's track record time.

But Waller and Yulong ultimately settled on sending her to the Champions Stakes instead of the race that stops a nation, in a move that has paid huge dividends.

"It was very special," Waller told Nine of Via Sistina's latest triumph.

"Winning the Cox Plate the way she did I think caught everyone by surprise, and then the pressure to back her up and go one more run.

"We spoke about sport analogies and having another game after a grand final and we were thinking about it constantly. But she's a very, very special horse, obviously.

"Don't underestimate how hard these horses work, we could see that. We just backed off in the last two weeks and gave her a good time, and it worked."

Earlier on Saturday, McDonald steered the Annabel Neasham and Rob Archibald-trained Sunshine In Paris to victory in the $3 million Champions Sprint (1200m).

That win, coupled with Via Sistina's victory, took McDonald's career tally to 104 Group 1 triumphs as he closes in on Damien Oliver's record of 129.

The 32-year-old New Zealand jockey is now in the box seat to win the Longines World's Best Jockey award for the second time, jumping ahead of UK star Ryan Moore in the standings.

Also on Saturday, Mr Brightside continued his love affair with Flemington with victory in the $3 million Group 1 Champions Mile for Ben, Will and JD Hayes.