The Perth Wildcats have kept their hopes of a third straight NBL championship alive with a stunning second-half performance to defeat the Illawarra Hawks 79-71.

Needing to win on the road in order to avoid elimination from the postseason, Perth produced something special at WIN Entertainment Centre on Saturday to send the semi-final series to a deciding third game at RAC Arena on Monday night.

The Hawks scrapped their way to a 31-28 halftime lead and with experienced Wildcats guard Mitch Norton limping off with a hip injury, the home side looked primed to reach the grand final series for the first time since 2017.

But Perth produced a remarkable turnaround with sharpshooter Clint Steindl and teenage guard Luke Travers inspiring a 32-point offensive explosion in the third quarter to turn the match in their favour.

Hawks import Tyler Harvey tried to fuel a fourth-quarter comeback, going on to lead all scorers with 24 points, but the Wildcats kept their cool in the final minutes to complete a memorable victory.

Coach Trevor Gleeson described the result as the gutsiest win he has been involved with during his eight-year tenure at the Wildcats.

"When Mitch went down ... we could have been a house of cards but we showed toughness, we showed heart, we showed passion, everything just makes you proud to be the coach," Gleeson said.

Forward John Mooney was a steadying presence with 18 points and eight rebounds while Steindl sparked the Wildcats with a 12-point cameo in the third quarter that included three triples.

Stepping into the starting lineup after a season-ending injury to two-time league MVP Bryce Cotton, 19-year-old Travers flourished in the biggest game of his career as he compiled 13 points, 10 rebounds and three assists.

"It's a progression from all his work that he's been doing over the last two years and now he's getting the opportunity and grabbing it ... he was brilliant out there today," Gleeson added.

Illawarra coach Brian Goorjian felt his squad's inability to find a rhythm on offence proved costly as they missed the opportunity to wrap up the series in front of their home crowd.

"I thought over the course of time they just wore us down," Goorjian said after the loss.

"Even when we were ahead of halftime the scoring was a struggle and we did a great job holding them down, but being able to do that for 40 minutes was just too much."

Facing the prospect of becoming just the second team in the past 26 finals matchups to lose a series after winning the opening game, Goorjian's focus ahead of Monday's decider is finding a way for the Hawks to score more easy baskets and ease the pressure on their half-court offence.