While Glory head coach Kenny Lowe has played down his team's poor form, Saturday's match at Allianz Stadium in Sydney will see two of the A-League's struggling sides clash for a crucial three points.
Perth have not won in four games, with only Newcastle Jets on a worse run of form, but in a boost for the Glory, they will face the most embattled club in the A-League in Sydney after the Sky Blues' fans staged a mass protest last week.
The Glory lost 2-1 to Melbourne Heart in Albury last week in sweltering conditions and need the likes of Nebojsa Marinkovic, Darvydas Sernas and Rostyn Griffiths to step up against Sydney.
Marinkovic, Sernas and Griffiths all arrived in the January transfer window and while they have not had long to get settled in Perth's purple shirts, Lowe needs a boost from the trio, as well as Glory's other mid-season recruit William Gallas.
Glory have 21 points from 18 rounds and sit in eighth, two points outside the finals positions, and while Lowe remains positive, another loss against Sydney could see Perth fall five points behind sixth-placed Wellington Phoenix.
"There are nine games left," Lowe said on Tuesday.
"We're three points off fourth, aren't we? What's all the hassle? Chill out, we'll be all right."
While Perth may be struggling, Sydney look to be just shy of complete disaster after their 3-0 loss to Adelaide United last week.
Sydney's fans held up banners during the game calling for the sackings of head coach Frank Farina, CEO Tony Pignata and chairman Scott Barlow.
When one supporter was ejected from Allianz Stadium for refusing to give up one of the banners, the rest of Sydney's active supporter group The Cove left the ground, before continuing their protest outside the venue.
The loss to Adelaide was Sydney's sixth in eight matches and their third in a row at home.
If Farina keeps his job until Saturday, it is hard to see him surviving another loss, especially after a falling out with two of his more experienced players - Nick Carle and Matt Thompson - during the week.
The struggles of Perth and Sydney will suit both Adelaide and Wellington as they host winnable games in Round 19.
Adelaide will welcome Central Coast Mariners to Coopers Stadium on Friday with the reigning A-League champions having lost 3-1 to Melbourne Victory last week, while the Reds have not tasted defeat at home in five games.
The Phoenix will host bottom-placed Heart on Sunday, while Newcastle will travel north to Brisbane hoping to turn their bad form around with a third straight win over the league-leading Roar.
Brisbane could move 10 points clear of second-placed Western Sydney Wanderers with a victory.
The Wanderers and Melbourne Victory completed their round 19 match in December as the latter have an AFC Asian Champions League play-off against Thailand's Muangthong United to play this weekend.
