Perth Wildcats centre Will Magnay has set himself the challenge of being more aggressive on the scoring end as the team tries to fill the huge void left by Bryce Cotton during the NBL grand final series.

Cotton was ruled out for the remainder of the season after undergoing surgery last month to relieve pressure from a haematoma in his left quadriceps.

The Wildcats overcame his absence to beat Illawarra 2-1 in the semi-finals, setting up a best-of-five grand final series against ladder-leaders Melbourne United.

Game one (Friday) and two (Sunday) will be at Perth's RAC Arena, before the rest of the series shifts over east.

Magnay only signed with the Wildcats in early May after being let go by NBA outfit New Orleans and he has been quiet in his nine matches to date.

In Monday night's series-deciding win over the Hawks, Magnay was scoreless and recorded just two rebounds before fouling out after 11 minutes of court time.

This season, Magnay is averaging 4.11 points, 4.22 rebounds and 1.78 assists per game.

The 23-year-old, who played three minutes for the Pelicans on March 23 before being waived by the NBA club, prides himself on what he can do on the defensive end.

But he knows he needs to lift his scoring output during the grand final series.

"I think the team wants me to step up scoring a little bit now that Bryce has gone," Magnay said.

"I'll look to be more aggressive. But I hang my hat on the defensive end and if I can make an impact there, I feel like I'm doing my job.

"Losing the MVP of the league has been tough. But the mentality here is next man up. No one is backing down. We're all going to out there and play as hard as we can.

"We've had to change a little bit up, because we can't just kind of hand the ball to Bryce and tell him to go score for us.

"It has built a bit of chemistry and a bit of camaraderie on the team. It's not a one-man show, we've got to do this together."

Melbourne United came from 17 points down in their semi-final decider against the Phoenix to post a 84-74 win.

United star Jock Landale was critical in the victory, tallying 27 points, eight rebounds and two blocks in a man-of-the-match effort.

But the Wildcats also have a standout big man in the form of John Mooney, who has quickly established himself as the NBL's double-double king.

Mooney is averaging 17.24 points and 11.37 rebounds per game this season and Magnay feels his on-court relationship with the star American "clicked" during the recent semi-finals series.