Currently, the teams are ninth and 10th in the Primeira Liga table, with only one point separating the away side from their hosts, who have played a game less.
Nacional began the year with a 2-0 home loss to the league leaders Sporting Lisbon last Friday, before bowing out to Porto in the latest round of the Taca de Portugal on Tuesday.
The Alvinegros are on a run of one win in five league games, and are just two points above the relegation zone as things stand.
With games at Benfica and Vitoria de Guimaraes to follow, it is imperative that they pick up victories in games against teams like Moreirense, who are in and around them on the log.
However, Luis Freire's men have lost six straight league games to Saturday's visitors, so they have it all to do in the latest meeting between the sides.
Moreirense are winless in both of their league fixtures in 2021, having played out a 2-2 draw against Vitoria de Guimaraes last Saturday, on the back of a 3-0 thrashing at the hands of Porto six days earlier.
Their poor run of form - three wins in 13 league games - stretching back to last year, has resulted in the appointment of a third different manager this season.
Vasco Seabra is the latest man tasked with steadying the ship at the Parque de Jogos Comendador Joaquim de Almeida Freitas, following his appointment earlier this month.
Like Nacional, Os Verdes e Brancos are also looking nervously over their shoulders, with only three points separating them from 17th-placed Boavista.
Nacional Primeira Liga form: WLLLWL
Nacional form (all competitions): LLWWLL
Moreirense Primeira Liga form: LDDWLD
Moreirense form (all competitions): WDWLDL
With the exception of Rui Correia, who was sent off in his side's defeat to Porto, Luis Freire has a full squad to pick from.
Neither of the Portuguese duo has featured for the away side since last October, where they both got injured 13 days apart.
Sori Mane has not played a single game for Moreirense this season, but he is expected to return to action in the coming weeks, as he nears full recovery from a muscle injury.
Nacional possible starting lineup:
Daniel; Vigario, Kal, Cesar, Freitas; Borges, Micael, Azouni; Riascos, Camacho, Rochez
Moreirense possible starting lineup:
Pasinato; Ferraresi, Pacheco, Rosic; Figueiredo, Soares, Soares, D'Alberto; Pires, Silva, Santos
We say: Nacional 1-1 Moreirense
Both sides have been closely matched over the course of the season, and we are expecting that to continue when they square-off against each other.