Ashcroft personified a tough outing for the premiers on Saturday in blustery and wet Barossa conditions, as they pulled away from North Melbourne late for a 26-point Gather Round win.
Jy Simpkin was outstanding, restricting the older Ashcroft to less than 20 possession for the first time since this time last season.
There was some aggression early in the game as Simpkin made his intentions clear and it set the tone for an afternoon of hard work.
Ultimately, the Lions made North pay for too many turnovers, especially in the third term, and they kicked the last three goals of the game for the 13.14 (92) to 9.12 (66) win.
Fagan noted that it's usually Lachie Neale or Hugh McLuggage that are tagged, but added Ashcroft's strong form meant the closer attention was not surprising.
"He deserves a tag, but what will happen is he will get a lot of learnings out of that," Fagan told AAP.
"It was something that, in a way, needed to happen to him.
"We'll go to work during the week on ways we can help him deal with that in a more positive way.
"He stuck his job, though. He was still trying his backside off for most of the game."
Fagan also noted that Ashcroft's tag meant Neale was able to get off the chain for 30 possessions and a game-high 10 clearances.
After two wins, this was a barometer game for the Kangaroos against the AFL's benchmark and they lost no friends. Well into the last quarter, they were less than two goals from the lead.
Luke Parker was outstanding in defence, Harry Sheezel was prolific through the midfield and last weekend's Rising Star nominee Cooper Trembath submitted a candidate for mark of the year with his soaring pack mark at the end of the third term.
But ultimately, coach Alastair Clarkson was left lamenting a lopsided 44-58 inside 50 count and his team's inability to get the game on their terms often enough.
"When you're playing the reigning premiers, irrespective of the errors they might have made in front of goal, you just have to capitalise on your chances." Clarkson said.
"We must have left five goals in the bank, I reckon.
"The dam wall is going to break at different stages.
"Despite being valiant, we just couldn't get the game on our terms consistently enough."
Just as Trembath soared for his third-quarter mark, Brisbane forward Lincoln McCarthy kicked a stunning goal from the boundary when the game was in the balance in the final quarter.
Fagan was furious at quarter time after North had kicked four-straight goals, later saying his players had gone away from their discipline around clearances
Veteran defender Dayne Zorko gave away a dumb 50m penalty at the end of the term, hitting Paul Curtis in the midriff and gifting him a goal.
While Zorko will come under match review scrutiny, it is probably irrelevant because he limped off in the second quarter with a game-ending calf injury.
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