Former Fremantle and St Kilda coach Ross Lyon has made a call on the game's best defender from the past 20 years, with the decision coming down to Hall of Famer Matthew Scarlett and premiership Tiger Alex Rance.

Speaking on the latest episode of The Coach, Lyon gave the three-time premiership Geelong full-back the nod over his Richmond counterpart.

"If you were to take a wholistic approach, and look at the similarities, they're both basically 194cm, six foot four, weight wise similar, durability both really strong, after their first two seasons, they both went on to average basically 20 games a season," Lyon said.

"If I wanted to build a club over a 10 or 12 year period, or even longer, Scarlett with the ball, he was incredible with the ball.

"His ability to stay composed under pressure, find the right option, and set up counter attacks, there is no doubt he is stronger there than Alex.

"I think the leadership, once he hooked into the group, he drove standards, he was the general of that backline even though Tom Harley was the captain.

"And culturally, they are different. Alex is an extrovert and at some point that caused some difficulties within that club, even though they smoothed it out.

"Overall, leadership and culture wise, smoother in what I would value more. The uniqueness, we celebrate it, but in the end …

"The whole package, particularly with ball in hand, and his ability to create a toe-poke, I'm biased toward Scarlett.

"I can't remember him getting touched up in a final."

Scarlett played 284 games fro the Cats, winning a best and fairest in 2003 and being selected in the All-Australian side on six occasions.

Rance, who retired in 2019 after 200 games with Richmond, won a Jack Dyer medal in 2015 along with five All-Australian selections.