Perth Glory coach Kenny Lowe has stoked the flames ahead of Saturday's preliminary A-League final against Sydney FC, suggesting it would be an embarrassment if their winger Diego Castro does not retain his crown as Player of the Year.

His bold statement was made ahead of a clash between Castro and the favourite to win the Johnny Warren Medal at Monday night's ceremony – Sydney FC midfielder Milos Ninkovic. Should the Serbian midfielder earn the highest individual honour in the A-League, Lowe believes it would not be deserved.

Lowe was adamant Castro is still the competition's most gifted and top-performing player having played a pivotal role in Perth's late charge towards the finals, scoring 13 goals and providing seven assists.

"If he doesn't [win the Johnny Warren Medal] it's a bit embarrassing, he's the best player in the league by a country mile," Lowe said. "Nobody gets rewarded, you only earn what you deserve. There are no rewards, everything is earned."

Perth enter Saturday's preliminary final at Allianz Stadium as rank outsiders having lost all four competitive games against Sydney this season, conceding 13 goals and scoring just two. While history is not on Perth's side, Lowe heaped pressure on Sydney to ensure their incredible season doesn't end unceremoniously.

Despite winning the A-League premiership and setting a plethora of new records on their way to their first silverware in seven years, Lowe hinted Sydney's season has counted for little yet unless they win the grand final.

"They want to create history and they'll be devastated if they don't," he said "They'll be devastated if they don't and everyone's been talking about them as the best team ever and rightly so. But the bottom line is that you've got to win something.

"They're a good team, they're well coached, they're highly organised, they've got some really good players. It will be a super game."