Currently, the eighth-placed hosts only sit below their opponents due to Santa Clara's 2-0 win over Belenenses earlier in the season, according to the Primeira Liga's priority on head-to-head results, while both sides sit just two points behind sixth-placed Vitoria de Guimaraes.
Belenenses come into Sunday's game on the back of consecutive victories, putting them in contention for a top-six finish.
Petit's side recorded an impressive 3-1 away win over Tondela last time out, in an important mid-table clash, as a Mateo Cassierra brace and a Miguel Cardoso penalty overturned Mario Gonzalez's early goal for the hosts.
That followed a 1-0 win at home to Portimonense, as Cassierra again got on the scoresheet to seal all three points for his side.
Having previously been threatened by relegation, O Belem have dragged themselves quickly up the table with four wins and 13 points from their last six matches, meaning they now stand in contention to finish in the top six of the Portuguese top flight.
Currently only trailing Santa Clara due to the head-to-head result earlier in the season, Petit's men will go ahead of their opponents and potentially leapfrog sixth-placed Vitoria de Guimaraes with what would be another impressive victory on Sunday.
Their opponents will also look for a win to cement their spot and push to move above Vitoria going into the final day of the season.
Santa Clara broke a five-game winless run with a narrow victory over strugglers Rio Ave on Tuesday.
That followed a run of five games without a victory in the Portuguese top flight, having picked up just two points in that time.
However, they have managed to stay within touching distance of an inconsistent Vitoria side, and two wins from their last two matches should see them seal a spot in the top six at the end of the campaign.
Belenenses will come into this game without midfielder Silvestre Varela, who will miss out through suspension after he was shown his fifth yellow card of the season last time out.
Mateo Cassierra will lead the line with plenty of confidence, having netted three goals in his last two games to take his tally to 10 goals from 30 league appearances this season.
Ramos is likely to keep the majority of his side unchanged after the positive result last time out, with Mikel Villanueva and Fabio Cardoso partnering up at the back while Rui Costa could again lead the line with the support of Carlos and Allano.
Belenenses possible starting lineup:
Kritsyuk; Silva, Phete, Ribeiro; Esgaio, Sousa, Sithole, Lima; Cardoso, Cassierra, Teixeira
Santa Clara possible starting lineup:
Ferreira; Ramos, Villanueva, Cardoso, Lucas; Lincoln, Nene, Morita; Carlos, Costa, Allano
We say: Belenenses 2-1 Santa Clara
Belenenses come into this game with plenty of momentum having quickly raced up the table, and we see them pulling off another impressive victory on Sunday to see them move into the top seven.
While the visitors did make a crucial return to winning ways last time out, we see them falling short against a Belenenses side who have hit form at a great time, and will be full of confidence.