Some of the country’s best male and female sprinters take to Sandown Park this Thursday in heats of the Harrison-Dawson and Sapphire Crown respectively.

The 64 greyhounds expected to start in both series combine for a staggering $7.71 million in prizemoney won, with $5.44 million of that coming from the 32 Harrison-Dawson runners alone.

The girls will get things started in race 2 (heat 1) with Cruising Debbie returning to Sandown Park for the first time since her Launching Pad triumph in March.

Without doubt the number one Sapphire Crown seed is recent Golden Easter Egg winner Mackenna. Since the win, she trialled extremely fast at Sandown Park then had a final hitout at Bendigo on Saturday.

The Harrison-Dawson heats kick off at race 6 and the sport's stars are out to play.

Afire, Big Energy and Trooper Tears start the series with a bang. Afire has flown in his four starts since resuming but now faces far classier opposition.

His kennel mate Morton headlines heat 2 and meets the in-form Shima Current.

Queensland gun All Natural is the biggest name in heat 3. He arrives in Melbourne on Wednesday and will go into the race without a look at Sandown Park.

Warm the popcorn up ahead of heat 4 with powerhouses Hector Fawley and Yachi Bale to meet again. The standout early speed will come from the inside courtesy of Launch Code and Funny Old Fellow which should give room for the stronger types to set up their race.

Catch in depth coverage from 5.45pm on the Watchdog App and Sky Racing Active.

The top two from each heat will advance to next Thursday's finals of the G1 Sportsbet Sapphire Crown and G1 Sportsbet Harrison-Dawson. Thursday's card will also feature heats of the Sportsbet Sandown Cup.

Box draws for both finals will be conducted on-track after race 10.