The NSW Waratahs have held out the Melbourne Rebels 18-16 to set the stage for a potentially decisive Super Rugby conference derby with the Brumbies in Canberra.

In a rollercoaster season of ups and downs, the Waratahs backed up their stylish win over the table-topping Hurricanes in Wellington with a hard-earned and bruising victory on Saturday night at ANZ Stadium.

Tries to Michael Hooper, Adam Ashley-Cooper and Rob Horne lifted the Waratahs to sixth on the ladder, four points shy of the Brumbies, ahead of the two arch rivals’ showdown on Friday night in the national capital.

The Waratahs defeated the Brumbies 28-13 in a spiteful encounter just three weeks ago in Sydney and another win would leave the titleholders’ finals fate back in their own hands.

A day after Wallabies and Waratahs coach Michael Cheika admitted he was contemplating trying to lure the great George Smith out of retirement for the World Cup, Hooper responded to the challenge in similar fashion as Brumbies breakaway David Pocock did on Friday night.

Cheika said he probably couldn’t squeeze three openside flankers into his 31-man World Cup squad, placing pressure on Hooper and Pocock to deliver – and they did.

Hooper couldn’t match Pocock’s powerhouse hat-trick, but he still produced a priceless man-of-the-match display to ensure the Waratahs kept the plucky Rebels at bay.

Like all three of Pocock’s tries in the Brumbies’ 31-18 home win over the Highlanders, Hooper collected the opening five-pointer of the night in the ninth minute from the back of a Waratahs rolling maul.

He then ran a beautiful line off a Tahs lineout win before putting Ashley-Cooper over in the 20th minute.

A two-try hero in NSW’s drought-breaking final win over the Crusaders, Ashley-Cooper returned to the scene of the Waratahs’ greatest triumph to bag his first of the season.

But with Bernard Foley missing both conversions and a penalty attempt, the Waratahs only led 13-3 at the break.

Two more long-range penalty goals from five-eighth Jack Debreczeni edged the Rebels to within four points of the Tahs – and effectively just a try from leapfrogging the defending champions on the ladder.

Horne’s five-pointer on the hour gave the home team some breathing space but a 74th-minute try to Rebels reserve Bryce Hegarty, on for fullback Mike Harris, set up a heartstopping finish for Waratahs fans.