The newly crowned NBL MVP scored 42 points in a 108-107 overtime thriller at RAC Arena and became the first player to nail 10 three-pointers in an NBL semi-final.

The reigning champions can progress to the grand final series against either the Sydney Kings or Melbourne United, with a win in Cairns on Sunday.

The Taipans led by nine points at half-time and by eight points midway through the third term, but in the end, 17 turnovers to three were too many for them to overcome.

Taipans coach Mike Kelly said you can't keep giving Perth and Cotton that many extra shots and expect to win.

"You can't turn the ball over here and can't give up a lot of offensive rebounds," he said.

"It's pretty simple; they got a lot more shots than us.

"We shot the ball really well, but didn't get enough of the shots."

Cotton had his hands full with DJ Newbill at times, scoring only five points combined in the second and third quarters.

But the champ dropped 14 points in the final term and then nine points in the overtime period, to see his team home.

Fellow All NBL First Five member Nick Kay was Cotton's main support, finishing with 23 points and nine rebounds. Veterans Jesse Wagstaff and Damian Martin were also important in a tense run home.

Cairns started slow, but they produced a monster second term, turning a nine-point deficit into a nine-point lead.

They dropped 32 points for the term, incredibly at better than 81 per cent.

Scott Machado (31 points for the game) dropped a monster bomb from almost two metres shy of the three-point line to get the Taipans to within two points. His teammates carried the momentum from that shot to the half-time buzzer.

Defensively, the Taipans lifted equally as good.

Perth coach Trevor Gleeson said the character of his side came though when they were being challenged.

"There are not many times you get outscored by 18 in the quarter and they shoot 56 per cent from the three and you win the game," he said.

"They were great, shooting at such a high percentage; put us under a lot of pressure.

"But we showed grit out there when we were down by nine points. We didn't lose focus; we started working well together again."

Cairns Cameron Oliver brought the aggression to the final with an impressive 19-point, 18-rebound display.

And as well as working hard on Cotton, keeping him scoreless in the second term, Newbill also contributed 25 points.

Perth shot only 16 points at 30 per cent in that second term. But Cotton ensured that improved after the break.

Australian Associated Press