Starting as the even money favourite from box four, the black chaser began well but was beaten for early speed by La Grand Logie (box seven) in the run to the winning post, before checking off the leader's heels around the first turn.
Down the back, Knight Sprite hooked to the outside and surged past the lamplighter, but was soon challenged by the strong Brad Hill Billy (box three) down the side. Swinging for home and Brad Hilly Billy looked the winner, but Knight Sprite had other plans, digging deep to muster on the inside and clinch victory by a head in 30.58.
Hunter Valley trainer Gayle Masterson was overwhelmed by her star greyhound's performance after the race.
“I thought he was in a bit of trouble with Brad Hill Billy right behind him, I was holding my breath until after he went over the finish line,” Masterson told Australian Racing Greyhound.
“I can't believe how hard he fought for that win in the last 50m – he really had to put in and he wasn't going to let anyone go past him.
“It just seems that every time there is a question mark about him lately he has an answer for it – he just keeps raising the bar.”
It has been a whirlwind ride for Masterson since Knight Sprite, a son of Magic Sprite and Jaydo's Neglect, started his career in September 2014, with the 31 kilogram speedster giving Masterson her first city winner along the way.
“We bought him and his sister at three months old.
“I always thought he was going to be a nice dog – I didn't think he would be this good – but he just keeps showing me how special he is every time he goes around lately.
“Before him I bred two litters which were only country dogs – but I had a ball travelling around with them – and if I have to go country with the next lot of dogs I have then I will be fine with that.
“Right now I am just enjoying every moment with him (Knight Sprite) while I have him.”
Another likely contender for the $250,000-to-the-winner series is Mitcharlie Mia, which made it five in a row when taking out the Group 2 Richmond Oaks on Friday night.
The Mitch Northfield-trained bitch had to work to find the front, but was emphatic in the run to the line, scoring by three quarters of a length over Star Torana in 30.66.
Watch Knight Sprite (4) winning the Group 2 Richmond Derby.