Welsh rivals Scarlets and Ospreys set for Pro12 play-off scrap
So it's all come down to this. The rivalry between Ospreys and Scarlets is one of the fiercest in Welsh rugby, and on the last weekend of the regular season. Scarlets are in the box seat.
Win at home to Treviso and the Scarlets are through. But if they slip up, and Ospreys win away at Leinster, the reigning champions, Ospreys, could yet edge out their rivals. And if anyone knows how to defy the odds and win in Dublin, Ospreys do.
The old derby matches between Llanelli and Swansea, and Llanelli and Neath can still bring a chill to the spine. And the current incarnation of the west Wales derby - while transformed by the sheen of professionalism - still stirs the blood and quickens the heart rate in a way few other fixtures can.
Yes, this rivalry doesn't need any extra spice, but this season it's entered another dimension, as the two have battled furiously for that fourth play-off spot. It's been a story within a story. A narrative that's grown in significance as the season has unfolded.
Scarlets' season got off to a flier, as they smashed the European champions, Leinster, 45-20. They led the pack for four weeks. Defending champions Ospreys looked anything but, as they limped through the opening rounds, losing their first three, and stumbling to 11th place.
But what better to sharpen their focus than a battle royale with their biggest rivals? And in round four, they upset the form book with a 23-16 win at Parc y Scarlets; a result that kick-started their title defence.
Ospreys began a steady climb up the table, while the Scarlets stayed in the play-off zone until week 12. It was then that the intrigue began. Since round 13, the two sides have occupied fourth and fifth spots, straddling the thin line between glory and oblivion. Remarkably they've swapped places on six occasions since then - like two boxers staring each other out, daring the other to blink first.
Last week, Ospreys blinked by falling to a heavy defeat against Glasgow. Scarlets seized the advantage, beating Cardiff Blues, and extending their home record to six wins in a row.
The eyes of the rugby world were focussed on west London this week, when the Lions squad was announced, bringing months of fevered speculation to an end. Of the 37 lucky ones who made the cut, 24 play their rugby in the Pro12. And it is here the gaze will return on Friday night, when all six matches kick off at the same time.
There will be plenty of Lions on display, all looking to roar louder than their opponents, knowing that the leader of their pride will be watching their every move, as they seek to manoeuvre their way into Test reckoning. It's a big night for Scarlets and Ospreys, and an even bigger night for rugby.
Watch Scarlets v Treviso on Scrum V Live, Friday, 3 May (19:30 BST)