Emma Stewart has created history by becoming the first Australian harness racing trainer to claim 100 Group 1 wins in her own right.

The Cardigan horsewoman reached the historic milestone with victory in the Nutrien Equine Alabar Farms 2YO Pacing Colts and Geldings Final at Menangle on Saturday night.

Stewart had three runners in the $175,000 feature, but it was First Responder that captured the victory under the urgings of driver Mark Pitt.

The son of Art Major sat behind stablemate and leader Major Celebrity for much of the 2300m trip and dashed home quickest to beat Shane Sanderson-trained Dangerous and that early front-runner.

It was the horse’s second win at start four.

“It is special,” Stewart told Sky Racing.

“It’s one of those things you never think is going to happen, so you didn’t want to have too high expectations tonight having the three favourites, but they got the job done so it was really good.”

Queensland-born Natalie Rasmussen has eclipsed 100 Group 1 wins, but most of her elite level triumphs have come in partnership with Mark Purdon in New Zealand.

Stewart has taken just over 20 years to claim the century of Group 1 winners, with her first runner as a trainer being in May 2002.

Her maiden Group 1 success came courtesy of Manwarra Hatrick, who produced a gutsy front-running effort for Brian Gath in the Vicbred Super Series 4YO Mares Final at Moonee Valley in 2007.

Ladies In Red and Poster Boy have been her most prolific Group 1 winners with five each, while Chris Alford has been her most successful elite level driver with 27 victories.

>> READ MORE: Emma set to reach historic training milestone