Craig Newitt has no doubts Overstep is a coming Group winner after recording a narrow victory at Flemington.

Overstep showed an explosive turn of foot at the 400m mark of the Barwon South West Region Handicap (1100m) on Saturday that had Newitt glowing in his post-race interview.

After settling back early, Overstep ($6) hit the lead inside the final 100m before holding off $5 favourite Invincible Al by a half-head, with Blue Tycoon ($11) 2-1/2 lengths away in third.

Newitt, who has teamed with Chris Waller's Flemington yard, said the stable had been teaching the filly to relax.

"I could have been a pair closer today but there's a fine line between being that length closer and over-racing and being that length back and relaxed," Newitt said.

"I would like to know what her split was from the 400 to the 200 metres because as soon as I came out from behind them she lengthened under a hold and put them away quickly.

"She was going to be a little vulnerable late but I was always confident of holding on."

Newitt said Overstep would be even better suited stepping up to 1200m, the distance of the Listed AR Creswick Series Final at Flemington on July 8.

Waller's Melbourne representative Johanne Taylor said the filly was likely to head towards that race, which could give her an important "black type" victory.

"As long as she keeps eating up and showing us that she's not at the end of her preparation, I'm sure we'll head in that direction," Taylor said.