Too many more heart-stopping finishes might not be good for David Mundy's heart, but coming from behind to clinch three successive wins is fuelling a growing sense of belief in the Fremantle camp.

Fremantle nailbiting win against North Melbourne on Saturday night, with Shane Kersten's snap in the final minute sinking the Roos by five points.

In round four, it was fellow recruit Cam McCarthy's goal-line toe poke that secured a stirring two-point triumph over Melbourne at the MCG, a week after Freo climbed off the canvas and overran the Western Bulldogs in the final term.

Fremantle trailed by 29 points early in the third term against North but, in an emerging trend, lifted late and scrambled home.

"It's always nice to win those close ones, but they're a little bit of a heart-stopper and too many of them will be a little bit bad for the health," Mundy told AFL.com.au.

"But I thought the boys really dug in, especially from half-time, and really ground out a good win in the end. 

"Talking about self-belief, I think there is, provided we have the right mindset when we go out to play."

It has been a significant turnaround for Fremantle since Ross Lyon's outfit was beaten by 89 points in round two against Port Adelaide and lost by 42 points to Geelong in round one.

Freo responded with six changes, calling up youth for the Bulldogs clash, and have looked reinvigorated since, with an emphasis on the basics – including a return to their trademark ferocious pressure. 

"We've certainly simplified what we've been speaking about Monday to Friday and how we review and our key points leading into games," Mundy said.

"I think that's really refreshing, especially for the age demographic we have at the club.

"It's really allowing our young guys to have simple focuses going into games and playing on instinct and not thinking too much.

"It may make it sound quite stupid, but it's really beneficial in making split-second decisions out there."

Freo's senior players have led the revival from the front, with superstar captain Nat Fyfe, Stephen Hill, Lachie Neale, Aaron Sandilands and Mundy playing starring roles.

Mundy has averaged 27 touches a game over the past three weeks, and slotted five majors, after being stationed deep forward for long periods.

The 31-year-old was clearly best on ground against the Kangas with 30 disposals and six clearances, exerting a huge influence after being swung back around the ball after half-time.

"It's certainly been refreshing (spending more time forward) and – prior to this week – being able to hit the scoreboard has been nice," he said.

"But rotating with Nathan (Fyfe) through there is allowing us to stay on the ground a little bit longer.

"I think it's been beneficial so far, we're still working on the chemistry of it.

"Even for the younger guys, it's really difficult to play 22 games inside mid. It really does take a toll on your body, especially with the flying that we do and how it lags recovery a little bit.

"Certainly I think it's the way football is going."

Fremantle suffered a late blow against North after Stephen Hill suffered a hamstrong injury.

The in-form midfielder is expected to be on the sidelines for three to four weeks, and will miss a huge Western Derby against West Coast on Saturday night, with both sides firmly in the finals hunt.

"They're always big affairs," Mundy said. 

"[The Eagles] are and about and they gave us a good pantsing in JLT1 this year, so it will be a good challenge for us."