The last of the day's 10 races will have a major impact on who will get in and who will miss out on the signature Queen's Birthday raceday.
Overzealous and Get Lucky are in a top-12 qualifying position in the 3yr-old trotters section of the Harness Jewels.
They will attempt to cement their positions when clashing in race 11, a rating 56 and faster handicap over 2600m.
Lone Star Lad and One Over Da Skye will attempt to use the same race to leapfrog their way into a top-12 position for the 4yr-old trotters section.
The quartet are among nine horses that have a realistic chance of booking their ticket to the Harness Jewels by securing enough in stake earnings tomorrow.
The Mitchell Kerr-trained A Taste Of Honey held the last qualifying position in the 2yr-old fillies section of the jewels, going into the weekend. The filly looks to have big chance of winning race 7, and cementing her spot.
Kerr starts Change Is Good in race 5 under much different circumstances. The 4yr-old mare cannot make the jewels, but could win and hinder the qualifying chances of some of her rivals.
Rival Feel The Money could jump from 16th position into a top-12 qualifying spot with victory in the junior drivers' race.
Sweet Mary, who starts from the back mark of 25m in race 9, the feature pace, occupied one of the top-12 spots in the 4yr-old pacing mares section prior to the weekend's racing.
Sweet Mary will clash with Donegal Art Chokin, who is relying on a win and other results to make the 3yr-old pacing fillies section of the jewels.
Though she is having just her first start, it would be possible for Simone De Beauvoir to qualify for the 2yr-old trotters section by winning race 1.
Prince Art looks one of the strongest winning chances of the non-Harness Jewels contenders racing tomorrow.
The Cran Dalgety-trained pacer starts for the second time this campaign in race 6.
"We gave him a nice break and when he came back he had to run against horses that had won five races," Dalgety said.
"He went a nice enough race and we are hopeful he is ready to win a race like this now."
