A week after riding a short-priced favourite to victory in the Flight Stakes, McDonald has hopes of causing an upset in Australia's other Group One 1600m race for three-year-old fillies.
McDonald won last Saturday's Flight at Randwick on $1.75 favourite Funstar while this Saturday his book of feature race rides at Caulfield includes the Anthony Freedman-trained Southbank in the $1 million Thousand Guineas against a field featuring $2.30 favourite Flit.
McDonald rode lightly raced Southbank for the first time when the filly finished second in the Thousand Guineas Prelude (1400m) and that was enough for him to predict a bright future for her.
"I love this filly," McDonald said.
"She's a beautiful filly and she's only going to get better as the trips get a bit longer.
"Seven furlongs up to a mile on Saturday will be ideal. She races on the pace and she's just a really progressive sort of horse.
"She'll be winning a big race over the spring."
Southbank was at $17 on Wednesday and is one of two Thousand Guineas chances for the Freedman stable along with Group One winner Lyre who is $5.50 second favourite.
"Lyre has got the runs on the board. She goes well at Caulfield and she's got an electric turn of foot," assistant trainer Sam Freedman said.
"Southbank is the fresh filly on the scene.
"So it is probably hard to split them. They are both very talented horses.
"With Southbank, whether it's this preparation or next preparation she'll be seen at the top level I'm sure.
"Both fillies seem to be peaking at the perfect time."
Lyre won the Group One Blue Diamond for two-year-olds (1200m) at Caulfield in February at the fourth run of her first preparation and Freedman said she was thriving ahead of her main spring target in the fourth run of this campaign.
The Guineas will be her first try at 1600m.
"She's versatile in all sorts of going so if she sees out the mile she will be fighting out the finish," Freedman said.
With Lyre's regular jockey Luke Currie ruled out through a careless riding suspension, Mark Zahra was called up to ride the filly for the first time.
The James Cummings-trained Flit was a luckless runner in the Prelude, finishing ninth after being held up for clear running in the final 200m.