Stinging from a big loss in Friday night's opening game, the Phoenix rose to the occasion at Sydney's Qudos Bank Arena on Sunday to claim their first-ever playoff win and set up a do-or-die clash on Tuesday for a spot in the grand final.

The underdogs lifted their intensity levels as the match developed into a slugfest over the first three quarters and Melbourne eventually faltered as the Phoenix charged home 24-9 in the final term.

Melbourne clung to a 77-74 lead midway through the fourth quarter but Izayah Le'Afa drilled a three-pointer and Mitch Creek fired in nine successive points to break United's resistance.

"I loved the endeavour of the guys tonight, it was poles apart from where we were last game and it's important that we found our feet and what it requires to make playoff basketball successful," said Phoenix coach Simon Mitchell.

Creek and Keifer Sykes led from the front for the Phoenix with 26 points apiece while Yanni Wetzell's (20 points, eight rebounds) relentless attack on the basket played a major part in United game-one hero Jock Landale being held to five points before fouling out of the contest.

"For a rookie professional to come out and put that sort of performance on a world-class player, it's a pretty special moment," Mitchell said about Wetzell's response after being soundly beaten by Landale in game one.

Sykes poured in 13 first-quarter points but Chris Goulding's hot start and Scotty Hopson's impact off the bench handed United a narrow 28-26 lead.

South East Melbourne kept up the intensity in the second term but poor shooting from three-point range proved costly as United held onto a 50-46 edge at halftime.

United maintained their four-point edge heading into the final quarter but South East Melbourne refused to go away and made their move once Landale fouled out with six minutes left to play.

Dean Vickerman gave credit to the Phoenix but felt the number of fouls called (56 in total) was over the top in comparison to game one, particularly with marquee forward Landale playing just 13 minutes.

"The contact was just not the same for the things that he got called for and the other things that are going on on the floor," Vickerman said about Landale's treatment by the referees.

"We need him on the floor and I hope that they look at this game and say yes, we got some of those (calls) wrong because I believe they did."

Australian Associated Press