A run of three straight defeats to start the campaign has left Petit's side at the foot of the Primeira Liga table, while their visitors have only collected one point from their three matches.
Match preview
After comfortably surviving the drop last season, succeeding thanks to their thriving defensive line, Petit's men headed into the new campaign with optimism, but it has not got off to an ideal start.
A 1-0 defeat to second-tier Mafra in the Taca da Liga first round provided a warning sign, before goals from Antonio Martinez and Luis Diaz condemned them to a 2-0 defeat to title-chasing Porto in the opening game.
O Belem then took on Maritimo in the second league outing, and they quickly went two goals behind as Andre Vidigal and Ali Alipour got on the scoresheet in the first 15 minutes, and while Alioune Ndour pulled a goal back on the stroke of half time, they could not find an equaliser and again fell to a defeat.
Their league losing run was stretched to three matches last time out, as they faced the tough task of a trip to defending champions Sporting Lisbon, with an early Goncalo Inacio goal and a 48th-minute Joao Palhinha finish making the difference in a 2-0 win for the hosts.
Now as just one of the two sides without a point, Petit's side will be desperate to stop the rot and put a positive result on the board on Friday, although they take on a side equally keen to reverse their fortunes.
Moreirense were also dumped out of the Taca da Liga first round by lower-league opposition at the beginning of the season, as second-tier Penafiel won a penalty shootout after the game finished 1-1.
That did not provide a good platform for the new campaign, as they look to build on last season's eighth-placed finish, and Os Verdes e Brancos got off to a losing start in the league when they took on title-chasing Benfica.
Lucas Verissimo and Luca Waldschmidt scored early to give As Aguias a two-goal lead, and while Rafael Martins pulled a goal back for Moreirense on the half-hour mark, they could not find an equaliser, despite Diogo Goncalves being sent off for their opponents early in the second half.
They then travelled to take on Santa Clara, and a dramatic final stretch took place as their hosts went into the dying minutes with a one-goal lead.
Yan drew Joao Henriques's men level in the 90th minute, but Carlos quickly put their opponents 2-1 up before Andre Luis hit the visitors' second equaliser in the 10th additional minute to earn their first point of the campaign.
They were not able to build on that last time out though, as goals from Steven Vitoria and Paulinho appeared to earn a 2-2 draw against Braga, only for a 95th-minute winner from Ricardo Horta to snatch all three points for the Archbishops.
Having lost two of their opening three matches, Os Verdes e Brancos will go in search of an elusive win on Friday to reverse their fortunes.
Belenenses Primeira Liga form:
Belenenses form (all competitions):
Moreirense Primeira Liga form:
Moreirense form (all competitions):
Team News
Belenenses come into Friday's game without midfielder Afonso Taira, who was sent off in the dying minutes of the defeat to Sporting Lisbon and will serve a suspension.
That only worsens their troubles in midfield, as Sandro and Sphephelo Sithole are both out of action, with the latter ruled out after a positive coronavirus test.
Another major loss could be important forward Matteo Cassierra, who was absent last time out after hitting 10 league goals last season.
Moreirense will remain without right-back Rodrigo Conceicao, who continues to serve a suspension after he was shown a red card just four minutes into his substitute appearance against Santa Clara.
They boast a threatening front line, with Yan, Rafael Martins and Filipe Soares all expected to keep their places.
Further back, Artur Jorge, Steven Vitoria and Lazar Rosic should again form the back three, shielding Mateus Pasinato between the sticks.
Belenenses possible starting lineup:
Felipe; Phete, Henriques, Ribeiro; Calila, Teixeira, Sousa, Boni, Akas; Nuno, Ndour
Moreirense possible starting lineup:
Pasinato; Jorge, Vitoria, Rosic; Ramos, Pacheco, Soares, Conte; Yan, Martins, Pires
We say: Belenenses 1-2 Moreirense
The visitors boast the stronger of the two squads, and have only narrowly fallen short to top sides in their two defeats, marking them as favourites on Friday as a result.
They have certainly shown more positive signs than their opponents, who have looked disappointing so far and could fall to another defeat as they take on a dangerous attacking outfit, with Belenenses' defence failing to click so far this campaign.