St Kilda has locked away exciting young midfielder Blake Acres until the end of the 2020 season.

The 21-year-old was already contracted for next season, however, the Saints opted to ward off any rival interest early and sign him for a further two years.

"It was a really simple decision for me," Acres said.

"I'm excited by the direction this club and playing group is heading.

"We are a tight-knit group and we're looking forward to getting back to work and making our mark next season."

Acres cemented his place in the senior side in 2017, playing 18 games and averaging 20 disposals.

"We saw Blake's confidence as a player improve this year as he found more consistency with his football," CEO Ameet Bains told the club's website.

"His size and athleticism really sets him apart as a midfielder and we saw him go forward on occasions and be really dangerous."