The Darren Weir-trained Shiny Buttons has stormed into contention for Thursday's Warrnambool Cup with a convincing win on the first of three days of racing at the country Victorian track.

Shiny Buttons firmed from $12 to $5 for the $200,000 Warrnambool Cup (2350m) after powering through the heavy conditions to take out the 1700-metre Open handicap by 4-1/2 lengths on Tuesday.

The seven-year-old moved to the second line of Cup betting behind stablemate Akzar at $3.30.

Weir said Shiny Buttons would be taken to the beach on Wednesday with the intention of being back at the track on Thursday.

"Hopefully he can pull up well and back up on Thursday," Weir said.

Shiny Buttons brought up a winning double for Victoria's premiership-leading trainer on the opening day of the three-day Warrnambool carnival after Top Brass won the 1200-metre maiden.