Penrith triumphed over Melbourne with a 22-14 victory, despite three players being sin-binned, strengthening their bid for a top-two finish.
The Panthers aimed to break free from their recent inconsistencies as Brian To'o, a player recruited from Papua New Guinea, scored three tries to give them a 22-0 advantage on Thursday night.
However, the defending champions struggled to find their best form as Liam Martin (professional foul), Lindsay Smith (repeated infringements), and Jack Cogger (high tackle) were sidelined for 10 minutes each in the latter part of the first half.
This marked the first instance since 1996 that Penrith had three players sin-binned in a single game, while Melbourne had Oryn Keeley also penalized for repeated infringements.
Panthers coach Ivan Cleary expressed his concerns about the referee's decision to sin-bin Martin for obstructing Sua Fa'alogo during a kick chase, stating, "A professional foul is actually a deliberate act. That wasn't, obviously."
Forced to play with 11 men for about three minutes, the Panthers struggled defensively, allowing the Storm to target right centre Izack Tago.
Melbourne narrowed the gap to eight points after Siulagi Tuimalatu-Brown's impressive try in the right corner with 20 minutes remaining.
Once Penrith was back to full strength, they managed to withstand a surge from Melbourne in the rainy conditions. Cleary noted, "It was pretty much just trying to keep the head above water, really, and fortunately the boys were good enough to get it done."
This defeat guarantees the 11th-placed Storm will miss the finals for the first time since 2010, despite being in a position where they already needed a miracle to qualify.
Coach Craig Bellamy lamented the slow start, saying, "We done a great job in the second half. But why couldn't we do that at the start of the game, in the first 20 minutes? We didn't do that, and that's why we got the result we got."
With this win, the Panthers climbed to the top of the ladder; however, they might not remain there as second-placed Sydney Roosters are set to face Wests Tigers this weekend.
The victory came as Cleary celebrated his 500th game as an NRL head coach, but his team showcased a mix of performance levels.
The match began positively when Martin deflected a Nathan Cleary kick, allowing Smith to deliver a superb pass to To'o.
To'o intercepted a stray ball from Fa'alogo and sprinted 60 meters for his second try, later receiving a quick pass from Cleary for his third.
To'o now has 102 career tries, placing him second on the club's all-time list behind Rhys Wesser (113), a 2003 premiership winner. Cleary praised To'o: "He's been an absolute stalwart of the team, a cornerstone of everything we've ever done."
The sin-binnings slowed the Panthers' momentum, and Cogger's high tackle on Tyran Wishart could result in suspension.
Replacing Blaize Talagi with the defensively sound Cogger was a strong tactical decision by Cleary, but with previous suspension this season for a similar offense, Cogger may face further scrutiny as finals approach.