Perth Spirit will meet Brisbane City in the inaugural National Rugby Championship grand final after stunning previously unbeaten Melbourne Rising 45-29.

Brisbane City and Perth Spirit have scored two upset victories in as many days, leaving third-placed City set to take on fourth-placed Perth in the inaugural National Rugby Championship (NRC) grand final next Saturday at Ballymore.

The shock of the weekend came on Saturday afternoon at AAMI Park in Melbourne, as the undefeated Rising fell to Perth, who had recorded only three wins from eight starts in 2014.

Sloppy ball handling was the order of the day for the Melbourne outfit, who were unbackable favourites to take out the 2014 crown after going through the regular season undefeated.

Stern defence, direct play with ball in hand and a solid set piece was enough for Perth to record the biggest upset of the competition.

The tone set by the Spirit in the first 15 minutes – in which they defended wave after wave of Rising attacks – was carried throughout in an inspired performance.

“We knew that they were going to be very direct and they’ve got some big boys in Mitch Inman and Lopeti Timani so we knew if they got on top in that first 15, they were going to run away with the game,” Perth captain Sam Wykes said.

“Our defence was a big key coming into this game and then, coming off the back of five efforts in a row defensively, we scored and built momentum from there.”

A home final was on the cards for Brisbane City when they took on the NSW Country Eagles in Gosford on Friday night and they put in a solid performance.

A brace of tries to former Queensland Reds fullback Brando Va’aulu at either end of the 80 minutes was influential for the travelling City side, who put together a 16-0 second half to romp home.

City will host Perth next Saturday at the spiritual home of Queensland rugby in front of what is sure to be a massive crowd.

The last time the two sides met in Perth, City were rank outsiders and recorded a last-gasp victory thanks to a Junior Laloifi try.

Add that to the always-fiery Reds-Western Force rivalry and the NRC’s first grand final becomes a tantalising prospect.