MAX KING endured one of those days, highlighted by two moments in the frenetic last quarter at Marvel Stadium.

With Port Adelaide's defence under siege on Sunday, the St Kilda key forward twice was out-muscled by Power key defender Brandon Zerk-Thatcher.

It capped a great game for Zerk-Thatcher, who combined superbly with Aliir Aliir to lead the Power defence in the crucial two-point win over the Saints.

St Kilda coach Ross Lyon also noted that being out-pointed by a smaller player can happen, depending on how the ball is delivered.

And given how scrappy the ball movement was, it was a tough game for a key forward.

But it was still a frustrating match for King, who only managed 0.2 and has kicked just 19 goals in 11 games this season.

SAINTS v POWER Full match coverage and stats

Still, Lyon saw it as a step forward for King, who went into the ruck late in the game.

He noted the Brisbane Lions have done the same with their key forward Joe Daniher.

"It just frees him a bit from getting sat on - when we're not getting a lot of clean ball to him, it can be hard," Lyon said.

"In a weird way, that's a bit of win for us as well. I really admired his mental (toughness) ... he took a step forward."

Port coach Ken Hinkley praised his two key defenders and was not surprised Zerk-Thatcher managed to out-body King.

"That's his strength, he's a physical player. It works well for him - he's a competitive bugger, he goes pretty hard all day," Hinkley said.

"He's a bit no-frills, if that's a polite way to describe him, but he's a real competitor and a contest player."

While Lyon saw signs of progress with King, it's likely fellow forward Jack Higgins will be having a word with his coach about taking set shots at goal.

Higgins had a very gettable kick late in the game that would have put his side back in front, but he inexplicably did not make the distance after trying a snap.

"He's pretty consistent in what he does. I will just ask him to 'stick to your routine' and if it goes sailing through, we're all happy," Lyon said.

"He might have to put that away, I don't know."