The Kangaroos looked set for an easy win in Sunday's match in Perth after racing to a 49-19 lead early in the second quarter.
But the Eagles, who possess the youngest and most inexperienced list in the AFL, slammed through eight of the next nine goals to turn the match on its head.
Elliot Yeo (19 disposals, two goals), Harley Reid (30 disposals) and Jamie Cripps (three goals) played key roles in the 17.9 (111) to 15.4 (94) win, snapping the club's 12-game losing run.
West Coast's young talent shone brightly.
No.1 draft pick Willem Duursma kicked two goals from 15 disposals as well as taking a stunning pack mark in the final quarter.
No.4 pick Cooper Duff-Tytler kicked two goals himself, while second-year forward Jobe Shanahan and Archer Reid also chipped in with a pair of majors each, along with mature-age recruit Milan Murdock.
"It was awesome. I think we saw them grow in front of our eyes today," Eagles coach Andrew McQualter said.
"I thought it was so exciting for our fans to see some of those young players stand up in huge moments in the last quarter."
Reid sustained a physical battering throughout the game but managed to stay on-task to have a critical influence on the contest.Â
North Melbourne forward Nick Larkey kicked six goals while Harry Sheezel (40 disposals), Luke Davies-Uniacke (32 disposals) and ruckman Tristan Xerri (25 disposals, 44 hit-outs, seven clearances) were also influential, though it wasn't enough for the visitors.
"We just had a few too many passengers today," North Melbourne coach Alastair Clarkson said.
"I thought West Coast had a more even contribution of their players than what we did."
The Kangaroos lost key defender Griffin Logue to a hamstring injury in the opening minutes of the match.
West Coast also suffered a major blow when key defender Harry Edwards - playing his first game back from concussion - suffered another concussion late in the opening quarter through an accidental arm to the head from teammate Matt Flynn in a marking contest.
Larkey feasted with three goals as North Melbourne piled on seven in a dominant opening term, with the Eagles' horror skill errors proving costly.
The margin sat at 24 points at quarter-time, but the Eagles turned the tables in the second term as their hunt and pressure reaped four turnover goals.
West Coast kicked eight goals to two in the third term to take a 30-point lead into the final change, and although North closed the margin to 11 points, the home side were able to settle and see out the win.
The biggest flashpoint of the game came after Yeo nailed a clutch set shot from the boundary after the three-quarter time siren.
While Yeo turned to the crowd to share the moment of magic, North Melbourne defender Charlie Comben felled Reid, sparking a melee, with the high contact set to attract the attention of the match review panel.
