After a remarkable start to their first season back in the top flight for 83 years, the hosts have begun to slide down the table, but they will be favourites against a Maritimo side sitting six points adrift of guaranteed safety heading into the weekend.
Match preview
A dip in form was always inevitable for Casa Pia, whose underdog story has just begun to falter since the turn of the year.
Last year's second-tier runners-up won six and lost just one of their opening eight league games of the season, with that solitary defeat being a narrow 1-0 loss to a Benfica side that has swept most before them this term.
At one stage, Filipe Martins's side sat as high as fourth in the standings, but a run of just two wins in their 10 league games so far this calendar year has seen them drop down to seventh.
That is still a more-than respectable position for a team competing in the top flight for the first time since 1940, and they have effectively already sealed their number one priority of Primeira Liga survival this season with 19 points separating them from the bottom three.
The Geese are only six points above 13th in a congested middle part of the table, though, so if their downturn in form lasts too much longer then their early-season dreams of pushing for Europe will be forced to make way for a battle to finish in the top half.
Goals have been the main issue for Casa Pia, who have drawn blanks in five of their last six league games - including Monday's 1-0 defeat to Famalicao - and 11 times from 24 outings this season, while they have only scored more than one goal on six separate occasions this term.
As a result, despite their relatively lofty league position, only one team outside the bottom three has scored fewer than Casa Pia's tally of 20 this season.
The Lisbon-based outfit could not wish for a better team to face as they look to fix those problems, though, with Maritimo possessing the worst defensive record in the division with 45 goals conceded from their 24 games.
Things have not been much better at the other end of the pitch either, with their tally of 17 goals scored the joint-worst in the division - a recipe which will always leave teams staring down the barrel of relegation.
Maritimo currently sit in the relegation playoff position, but are six points adrift of 15th-placed Estoril and only one point above both Pacos de Ferreira and Santa Clara in the automatic relegation places.
Remarkably, though, that is the best position Jose Gomes's side have found themselves in all season, having never truly recovered from losing all of their first eight games of the campaign, including heavy defeats to Porto, Braga and Benfica.
It was not until October and their 11th game that Maritimo picked up their first Primeira Liga win of 2022-23, but there have been more positive signs so far this year, with three wins from their 10 top-flight outings in 2023, including a 1-0 triumph over Sporting Lisbon.
However, they have lost six of their last seven games stretching back to the end of January, picking up only three points from a possible 21 in that time, suggesting that their mid-season improvement of only two losses in the space of nine games is now well and truly over.
Just one of their victories all season have come on the road, leaving Maritimo with the worst away record in the division ahead of their trip to the grand stage that is the Estadio Nacional this weekend.
Casa Pia Primeira Liga form:
L
D
D
L
W
L
Casa Pia form (all competitions):
L
D
D
L
W
L
Maritimo Primeira Liga form:
L
L
L
W
L
L
Team News
Casa Pia will be without Angelo Neto for this match after he picked up his fifth yellow card of the season in the 1-0 defeat to Famalicao last time out.
Eduardo Fereira was taken off at half time in that match and could be replaced by the returning Lucas Soares in an otherwise unchanged starting XI.
Rafael Martins remains a doubt for the home side, while Leo Natel is sidelined through injury.
Maritimo also have suspension concerns, with Joao Afonso and Andre Vidigal both ruled out of this match for an accumulation of yellow cards - the former being booked without even getting on the pitch in the defeat to Benfica last weekend.
However, there is better news with Val Soares and Rafael Brito both returning in midfield after suspensions of their own.
Vidigal's absence could pave the way for Percy Liza to start in attack, but Diogo Mendes and Geny Catamo are both still sidelined through injury.
Casa Pia possible starting lineup:
Batista; Fernandes, Zolotic, Varela; Beni; Soares, Taira, Baro, Lelo; Clayton, Godwin
Maritimo possible starting lineup:
Carne; Junior, Costa, Mosquera; Winck, Val, Brito, Xadas, Costa; Moreno, Liza
We say: Casa Pia 1-0 Maritimo
With two of the division's lowest scorers on show, this looks likely to be a tight affair that could be decided by a single goal.