LOCKDOWN defenders often go unheralded, by nature of their job. They do what needs to be done to win games, nullifying dangerous forwards while their more flashy and eye-catching teammates receive the plaudits.

So while St Kilda backman Daniel McKenzie's fresh three-year contract, keeping him committed until the end of 2022, might be queried in some quarters, close observers of the Saints know how important he has become.

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The club's defensive coach Henry Playfair explained to AFL.com.au what the 22-year-old offers.

"Plenty is probably the one-word answer," Playfair said.

"His competitiveness is probably No.1. He just cracks in every minute of the game all the time, which you noticed last year, even though we weren't going well. He was flying the flag for 120 minutes. That's probably his bread and butter.

"Outside of that, he's versatile, he can play on talls and smalls, he's got good pace, he's got a good leap, he can intercept mark it and his direction is really good. His voice is awesome across the ground."

It's taken McKenzie a while to establish himself in the senior side. Niggling injuries have often interrupted him since being drafted at pick No.22 in 2014 but a magnificent last quarter in St Kilda's thrilling comeback win over Gold Coast in round 13 last season has proved the turning point of his career.

Coach Alan Richardson looked on the brink of being sacked going into that final term. The team hadn't won in almost three months and trailed the lowly Suns by 31 points but McKenzie's relentless approach dragged the Saints back into the contest.

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It proved pivotal in the development of someone who didn't always have the belief he perhaps should have, for a player of his ability.

"That was big for me. I think it just gave me a bit more confidence in myself," McKenzie told AFL.com.au.

Dan McKenzie has stepped up when it matters! #AFLSunsSaints pic.twitter.com/a2fpH0QXP5 — AFL (@AFL) June 16, 2018

Rehab manager Marcus Krygger has helped McKenzie through some tough times while skipper Jarryn Geary has been influential in building him up.

"I think he (Geary) sees a lot of the potential that the coaches see that I might miss sometimes, so his belief in me increased my own confidence," McKenzie said.

The athletic left-footer finished the campaign so well he ended up being 10th in the best and fairest, despite lining up in just 13 games in what was a dire 2018 for St Kilda.

"That was a massive surprise," McKenzie said with a laugh.

It was reward for consistently limiting the influence of his direct opponent, who he was assigned to each week.

The Saints have changed the way they defend this year, scrapping a strict man-on-man approach for a more system-based style, but McKenzie continues to thrive.

"I still do enjoy… trying to get the footy myself a little bit but if the team wants me to do that (shut someone down), I'm more than happy to do that," McKenzie said.

"I've found something that I'm good at so I'm happy to keep doing that if it's going to keep getting me games."