Foreteller has capped another big day for the all-conquering Chris Waller stable by helping the trainer to his first interstate Group One double.

Foreteller's half-head win in Saturday's Underwood Stakes at Caulfield gave Sydney's premier trainer a second Group One for the day after Sacred Falls defeated stablemate Royal Descent in the George Main Stakes at Randwick.

The win also announced champion rider Glen Boss's return to the Group One spotlight, giving the three-time Melbourne Cup-winning rider his first Group One success in a year.

One of the elder statesman of Waller's team, eight-year-old Foreteller ($6.50) produced a finishing sprint he is renowned for to defeat last year's Cox Plate runner-up Happy Trails ($10) to claim his third victory at racing's elite level.

"He's come through the grades and he's part of the furniture," Waller said of the Cox Plate-bound Foreteller after watching the race from Randwick.

Import Crackerjack King ($51) took up the running in the 1800m race and jockey Michael Walker was happy to sit four or five horses off the fence throughout and was even wider into the straight.

He kicked strongly in his third run back from a two-year injury absence but was collared late by Happy Trails and Foreteller.

Foreteller burst through to claim his first Group One since last year's Makybe Diva Stakes and Boss's first since Rebel Dane in the Sir Rupert Clarke Stakes last spring.

"This is an important race for the spring and it's an important one for me too," Boss said.

"It's been a long time between drinks for me in a Group One."

Boss is hoping it is the start of a big spring carnival and savoured the moment.

"I'm here. I'm fit. I'm riding well. I feel as enthusiastic as ever and just need opportunities," he said.

"I know I can do the job just as well as anyone out there. I've been doing it a long time. It's just a matter of getting on horses like this and the results will be there."

Trainer Paul Beshara insists Happy Trails is on track for his Turnbull Stakes defence next start and an attempt to go one better in the Cox Plate.

"I was hoping he would run in the first four but for him to nearly win, it's onwards and upwards," he said.