While the clubs sit in 11th and 12th place respectively, they remain just four points clear of the relegation zone with six games left in the season.
Having scored just 19 goals from 28 fixtures this campaign, it can be argued with justification that Belenenses are fortunate to be sitting in close proximity to mid-table.
Nevertheless, Petit's side have recorded 16 points from their last 12 fixtures, potentially moving the club to within a couple of wins of securing safety.
Everyone associated with the club will still be frustrated with letting slip a 2-0 lead against Sporting Lisbon on Wednesday, conceding two late goals to settle for a share of the spoils.
On a positive note, it was another point on the road against a top-four outfit having recently earned a 1-1 draw with Braga.
Mateo Cassierra scored each of the three strikes in those two fixtures, taking his tally for the season to seven in 18 starts and nine substitute outings.
Gil Vicente are another team who have benefitted from a much-improved run of results with four victories coming from just six encounters.
While Ricardo Soares was naturally disappointed with losing 3-0 to Famalicao on Thursday, two of the three goals came in added-on time while they were reduced to 10 men.
Three successive victories have been recorded away from home, a remarkable improvement on previously taking just eight points from their previous 11 fixtures on the road.
The most recent of those triumphs came at Benfica, and Soares will have every confidence that his side can get back on track at Estadio Nacional.
While Petit used a 5-4-1 formation at Sporting, the Belenenses boss will consider selecting a more attack-minded starting lineup for this contest.
Gil Vicente will be without Ygor Nogueira after the centre-back was dismissed in the last game.
Belenenses possible starting lineup:
Kritsyuk; Silva, Henrique, Ribeiro; Esgaio, Yaya, Sousa, Lima; Varela, Cassierra, Cardoso
Gil Vicente possible starting lineup:
Denis; Pereira, Fernandes, Rodrigao, Talocha; Carvalho, Mineiro, Pedrinho; Fujimoto, Marques, Lourency
We say: Belenenses 1-1 Gil Vicente
While both teams are aware of the potential rewards on offer with maximum points, they can also ill-afford to record a defeat. With that in mind, we feel that this contest could prove to be relatively uneventful, ending in a low-scoring draw.