The first time driver Dexter Dunn sat behind four-year-old female trotter Jiggy Jog S this season he was amazed by her transformation.

“I couldn’t believe how much she filled out,” said Dunn, who was the regular driver behind the Ake Svanstedt-trained mare last year when she finished no worse than second in 11 of 13 races, winning eight and earning $1,046,819.

“She was quite narrow last year. She looked as if she could get a lot stronger, and she did. She’s stronger, and even mentally, she’s really stepped up her game. It’s always exciting to see them come back like that, especially when she already had such a good year last year.”

Jiggy Jog S (pictured above) ended her 2022 campaign with four consecutive victories, which included the Kentucky Filly Futurity and Breeders Crown, and has opened this year with three consecutive wins. On Saturday, she will attempt to push her win streak to eight when she competes in the $230,000 Graduate Series Open Trot final for four-year-olds.

A daughter of Walner-Hot Mess Hanover, Jiggy Jog S will start from post one and is the 2-5 morning-line favourite. She is the lone mare in the eight-horse field. Two females have won the Graduate Series Open Trot final in its eight-year history: Atlanta in 2019 and Ariana G in 2018. (Last year, there was a separate division for mares, which was won by Bella Bellini.)

Jiggy Jog S served notice that she was ready to roll this year when she won the first round of the Graduate Series in 1:50.3 on June 3 at Woodbine Mohawk Park. Only one trotter has ever gone faster in Canada, Atlanta, who won the 2019 Armbro Flight in 1:50.2.

On June 16, Jiggy Jog S won the second leg of the Graduate in 1:50.3 at The Meadowlands, giving her the fastest mile in the U.S. for a female trotter this season. She sat out the third round on June 24, which was won by Keg Stand, and returned to action last week to capture the Six Pack Mares Trot in 1:51 at the Big M with Svanstedt in the sulky for the event.

“She’s very versatile now,” said Dunn. “Last year, I mostly raced her off a helmet and not as much on the front, but this year, she doesn’t really care. She was on the front and went a big mile up in Canada in her first start and came back the next start and was third-over and was just as good. She’s got the toughness and she’s got the speed. Those are great qualities to have.”

For her career, Jiggy Jog S has won 13 of 27 starts and earned $1.39 million for owner Jorgen Sparredal.

Dunn and Svanstedt will team up with another morning-line favourite one race later on Saturday in the $240,000 Graduate Series Open Pace final. Dunn will drive Stonebridge Helios, who drew post five and is the 2-1 choice over 5-2 Mad Max Hanover, who will leave from post four with Tim Tetrick driving for Jake Leamon.

Stonebridge Helios joined the Svanstedt Stable this year and has a win and a second in three races, all in divisions of the Graduate Series. He was sixth in his debut at Mohawk before winning in 1:47 — the fastest mile by a four-year-old this season — on June 16 at The Meadowlands. A week later, he finished second to Mad Max Hanover, who won in 1:47.4.

“He was super in that second start when he won,” said Dunn. “In the last start, it was a bad drive from me. I thought the horse’s performance was great, I wasn’t happy with my performance. But that mile he put up two starts ago was super. When I let him roll, he liked it. He got to the front and sort of swelled up. He was great.”

Dunn said equipment changes after Stonebridge Helios’ first start have made a difference.

“He raced good in Canada, but he was sort of all over the place,” said Dunn. “He had an open bridle and was running in and running out, but still put in a good mile. They changed his shoeing and put a closed bridle on him for the second start and he was much better.”

Stonebridge Helios, a son of Sunshine Beach-Ken Doll J, has won 11 of 20 lifetime races and earned $585,380. He is owned by John Fleischman and breeder Angie Stiller.

“He’s got a big motor,” said Dunn. “Hopefully, he can race off a helmet well too, but he likes to be rolling, I think. He’s got a big engine.”

Racing begins at 6:20 p.m. (EDT) at The Meadowlands, which also hosts two eliminations for the Meadowlands Pace on Saturday. Free TrackMaster past performances for the Big M will be available on playmeadowlands.com.

(With files from USTA)