Perth Scorchers are set to load up their top-order batting for the sudden-death match against Sydney Thunder tomorrow night.

Returning captain Mitch Marsh is tossing up whether to bat at No.3 or No.5 while his brother Shaun is set to open in his first Scorchers appearance of the summer.

The only certainty is that Ashton Turner will remain at No.4 where he has been a revelation this summer, with his brutal yet precise onslaughts bringing 302 runs at a strike rate of 133.63.

“The form that AT is in means he will probably stay at four,” Mitch Marsh said.

“You will probably see me at three or five.

“I love finishing off an innings and that is where I have done my best batting, especially for the Scorchers.

“I would like to be batting as high as I can but for the team’s sake I might be at five.”

The Scorchers are desperate for the win that would keep their season alive and know that a loss at Optus Stadium tomorrow would end their chances of playing finals in all eight seasons of the Big Bash League.

The brittle top order has proved the team’s weak point, with veteran Michael Klinger just holding on to his opening position. He has scored 115 runs at a strike rate of 83.33.

Marsh identified the batting problems as a key to Perth’s struggles but was confident his team could respond before it was too late.

“There are big moments in every game of T20 cricket and we have prided ourselves over the past seven years at winning those big moments,” he said.

“There have been a few key moments this season that we haven’t won. We win those two or three moments and we are sitting second on the ladder.

“Execution is a big thing in T20 and there have been times we haven’t executed with the bat and found ourselves in trouble early.”

The Scorchers will be without their international all-rounder David Willey for the rest of the tournament while Ashton Agar (finger), Sam Whiteman (quad) and Cam Green (back) are not likely to be available for any of the remaining five matches and finals. Willey will return to England immediately after damaging a shoulder in Perth’s recent loss to Hobart.

Sydney Thunder capped a forgettable week with a 12-run loss to Melbourne Renegades at Spotless Stadium last night.

After being set 153 for victory, the Thunder were unable to find momentum and managed 5-140 from their 20 overs as the Renegades jumped into second spot.

The hosts would have leapfrogged the Renegades and Sydney Sixers into second spot, behind Hobart Hurricanes, with a win.

But after their clash with Brisbane Heat was abandoned last Thursday over a light-tower failure and the resultant points split — which Cricket Australia upheld yesterday — their loss to the Renegades leaves them fourth and with a fight on their hands to make the finals.

Aaron Finch anchored the Renegades innings with 54 off 38 balls.