Josh Mansour snubbed Canberra because his heart belonged to Penrith, but his decision not to join the Ricky Stuart revival created a Green Machine try-scoring freak named Jordan Rapana.

Mansour and Rapana will go head to head in a mouth-watering wing battle at Canberra Stadium on Saturday night, two years after Mansour toured Raiders headquarters before turning down a contract offer.

But Raiders champion fullback Brett Mullins believes NSW and Australian flyer Mansour would struggle to even make it into Canberra's starting line-up after a sliding-doors moment.

Rapana is on the verge of equalling Mullins, Jason Croker and cult-hero Noa Nadruku for the most tries in a Raiders season.

Rapana needs to score just once to draw level with the 22-try mark set by the legendary trio in the Raiders' golden era of the early 1990s.

"Records are there to be broken ... I hope he scores 10 tries and wins the game," Mullins beamed.

"I reckon he's a better winger than Mansour anyway, that's in my eyes. It will be great to watch, I'm looking forward to it.

"Rapana's got an all-over game, he's a footballer. Mansour is a little, short, strong bugger. But Rapana is more of a footballer, that's where I see the difference."

The Raiders and Panthers will face-off in a do-or-die semi-final battle on Saturday night, with the winner advancing to the preliminary final against Melbourne.

The new generation Raiders have been built on sliding-door moments and opportunities in the capital.

When Michael Ennis said no to a Raiders offer, Canberra signed Josh Hodgson.

When James Tedesco back-flipped on a contract commitment, the Raiders had enough money to sign Blake Austin.

When Mansour re-signed with the Panthers, the door opened for Rapana to get game time.

And when Daly Cherry-Evans signed with the Gold Coast Titans before backflipping, the Raiders swooped on Aidan Sezer.

Rapana and centre Joey Leilua have formed a devastating right-side combination and have scored 32 tries between them.

The Panthers hope their left-side combination of Mansour and Tyrone Peachey will be able to handle the heat and the duo have scored 28 tries this year.

The Raiders won 10 games in a row before losing to the Cronulla Sharks by two points. The Panthers have won their past six games.

"Penrith are in the top eight for a reason and it's going to be a tough game – they play a similar style to what we do," said Raiders enforcer Josh Papalii.

"A lot of people forget that we're still young teams and developing. For both of us to make it this far is pretty good and it sort of shuts up a lot of the critics. That's why you play sometimes.

"Hopefully the 'Leipana' [Leilua and Rapana] connection can score four tries each and dominate their edge."

NRL SEMI-FINAL

Saturday: Canberra Raiders v Penrith Panthers at Canberra Stadium, 7.40pm. Tickets available from Ticketek.

Raiders team: 1. Jack Wighton, 2. Edrick Lee, 3. Jarrod Croker, 4. Joey Leilua, 5. Jordan Rapana, 6. Blake Austin, 7. Aidan Sezer, 8. Junior Paulo, 9. Josh Hodgson, 10. Shannon Boyd, 11. Josh Papalii, 12. Elliott Whitehead, 13. Sia Soliola. Interchange: 14. Kurt Baptiste, 15. Luke Bateman, 17. Joe Tapine, one to be added.