Penrith superstar Nathan Cleary has suffered a suspected horrific compound fracture of his lower leg in a sickening incident during the Panthers’ NRL preliminary final against Newcastle moments ago.

Cleary went down in agony following a tackle by Knights utility Phoenix Crossland late in the first half at Accor Stadium, with the seriousness of the injury immediately apparent.

The broadcast team believe Cleary had suffered a compound fracture.

It is a devastating blow for one of rugby league’s biggest names, whose season is over and whose availability for the upcoming Rugby League World Cup is in extreme doubt.

Cleary had entered the preliminary final carrying a separate stress-related bone injury in his right foot, suffered during Penrith’s qualifying-final victory over the Sydney Roosters.

That injury prompted coach Ivan Cleary to make a dramatic late change on Sunday, moving his champion halfback to the interchange bench and starting Jack Cogger alongside Jack Cole. Cleary was eventually called into the contest before disaster struck.

The injury brought a grim halt to what had been a gripping preliminary final, with players from both sides clearly concerned as Cleary received treatment.

Penrith, however, responded almost immediately.

Prop Lindsay Smith crossed for a crucial try shortly before half-time and Blaize Talagi added the conversion, sending the Panthers into the sheds leading Newcastle 14-6.

The stakes could hardly be higher.

Penrith are attempting to return to the NRL Grand Final after missing last year’s decider, while Newcastle is chasing its first Grand Final appearance since winning the premiership in 2001.

Waiting for the winner are the Sydney Roosters, who booked their place in next Sunday night’s Grand Final with a 36-20 preliminary-final victory over the Dolphins on Friday night.

But for Penrith, the immediate concern will be Cleary and an injury that has brought his season to a brutal end just one victory away from another Grand Final.