Canberra slipped to third on the WNBL ladder after falling to a rampant Southside Flyers outfit 101-82 at Townsville Stadium on Sunday afternoon.

The Capitals' third loss in five outings sends them into a do-or-die minor semi-final against the Melbourne Boomers on Wednesday, while Southside and Townsville will play off for a place in the grand final.

The winner of the minor semi-final then faces the loser of the major semi-final on Friday, for the right to advance to Sunday's grand final.

A win over Southside would have seen the Capitals finish on top of the table but now they are in dangerous territory after turning in a "disappointing" effort against the top seed, with Townsville surging into second on the back of a 70-64 win over Melbourne.

MORE SPORT

"We've got a group that has won before, and the majority of the group has come back from our championship, whether it be the first one or the second one. We're confident we will play and bounce back after this," Goriss said.

"It's a loss, but we still get to play finals basketball and that's what it's about. We're one step away from being in that preliminary final, and even though we'll be in a knockout, we've got the experience and we have certainly got the talent to win on Wednesday.

"Finals basketball to what regular season basketball is, especially in this hub environment. We've never been in a one-off final before which is something new.

"With the experience of playing in those three-game series and big games with [Marianna] Tolo and Kelsey [Griffin], [Maddison] Rocci has been around for it, Abby [Cubillo] is playing a bigger role, so is Keely [Froling], that group is hardened for finals basketball.

"Hopefully that shows come Wednesday."

Tolo posted an equal game-high 23 points against Southside but the Capitals had no answer for a Bec Cole masterclass, scoring 23 of her own.

The Capitals trailed 14-2 in the blink of an eye against a Flyers outfit which seemingly couldn't miss from long-range in the absence of captain Jenna O'Hea.

Just as soon as the reigning champions slashed the margin back to one midway through the second quarter, a Southside barrage would see it blow out as far as 16.

The Capitals closed the gap to four points at half-time, with Southside's 49 points the most Canberra had conceded in the opening half all season.

But any hopes of shooting down the Flyers seemingly evaporated during the third quarter as Southside piled on 32 points, with Canberra's attempts to run them down ultimately futile.

"To give them 22 points off our turnovers and 22 fastbreak points, we really just gave them 44 points for the game and it's not where we wanted to be," Goriss said.

"It was a big game for us to finish in the top two, but the overriding factor is we're in the top four. Whether we get one bite at it or two bites, we're in the top four and we've just got to be better come Wednesday.

"In a way we've got to park it, learn from it very quickly, learn what we need to do better and where we let ourselves down, and move on and prepare for Melbourne as best we can."

AT A GLANCE

WNBL round five: SOUTHSIDE FLYERS 101 (Bec Cole 23, Liz Cambage 18, Sara Blicavs 16) bt CANBERRA CAPITALS 82 (Marianna Tolo 23, Jade Melbourne 12, Kelsey Griffin 11) at Townsville Stadium.

WNBL FINALS

Major semi-final: Wednesday, December 16 - Southside Flyers v Townsville Fire at Townsville Stadium, 6pm.

Minor semi-final: Wednesday, December 16 - Canberra Capitals v Melbourne Boomers at Townsville Stadium, 8pm.

Preliminary final: Friday, December 18 - Loser of major semi-final v Winner of minor semi-final at Townsville Stadium, 7pm.

Grand final: Sunday, December 20 - Winner of major semi-final v Winner of preliminary final at Townsville Stadium, 3pm.