Penrith's push for a fourth consecutive NRL premiership has been rocked after star halfback Nathan Cleary injured his left shoulder in the 24-22 loss to fellow heavyweights Melbourne.
Cleary went down clutching his left shoulder following a shot from Storm forward Trent Loiero while the scores were locked at 22-22 in the final 15 minutes of Thursday night's game at BlueBet Stadium.
With his arm apparently in a sling, the 26-year-old watched from the sheds as the Storm clinched victory in a seesawing affair that lived up to its billing as one of the match-ups of the season.
Melbourne's Nick Meaney kicked the winning penalty goal with eight minutes to play after Panthers prop James Fisher-Harris was penalised for flooring Jahrome Hughes late.
With Cleary off the field, Dylan Edwards attempted a two-point field goal to level the scores just before the final siren but his attempt fell short and the Storm held on.
Cleary has suffered injury blows throughout the Panthers' title dynasty, most recently missing two months with a hamstring issue, spending time out with a right shoulder injury in 2021 and through suspension in 2022.
But navigating a finals series without the star halfback would be a new and greater challenge for the Panthers, who would likely need to parachute Daine Laurie or Jack Cole into the halves to partner Jarome Luai.
Cleary was having an uncharacteristically quiet game prior to the injury but had previously been outstanding since returning from injury last month to help the Panthers firm as premiership favourites.
Thursday's win moves the Storm two wins clear atop the NRL ladder and almost guarantees them the minor premiership with three rounds to play.
But they could lose prop Nelson Asofa-Solomona in the run to finals after he was sin-binned for making high contact on Laurie in a shot that also knocked teammate Cameron Munster to the ground with a bloodied face.
Even with Cleary, the Panthers were far from their brilliant best, giving up a double digit lead for the third time in five games as they fell behind 10-0 early.
Cleary gave away the shoulder charge penalty that put Melbourne in position to extend their lead to two tries through Eliesa Katoa and put a pass to the deck while Penrith chased their first points.
Panthers co-captain Isaah Yeo had his best game of the season, helping his side to their first try by drawing Munster in and passing off to Lindsay Smith.
It was also Yeo who put the Panthers in for their first lead of the night, tearing down the left edge before Casey McLean kicked through the line to put Dylan Edwards over in the second half.
The Panthers looked primed to go on with the contest after McLean dived over only minutes after Asofa-Solmona was sin-binned, with Munster also off for a head injury assessment.
But Tyran Wishart skipped through the Panthers' defence to level the scores with 20 minutes to play before Meaney's penalty goal sealed the result.