The visitors will be looking to build on their 3-1 victory over basement side Boavista last time out and put some real daylight between themselves and the bottom three.
Since Petit's men pulled off a shock victory over Braga at the start of December, they have struggled for any sort of form in the league.
A 1-0 loss to Portimonense in midweek means Belenenses have picked up just one point from a possible 15, a run that has seen them fall to 17th in the league standings.
Remarkably for a side in their lowly, precarious position, Os Azuis do Restelo have the joint-second best defensive record in the division, leaking just 12 goals in 14 games.
However, it is in attack where their problems lie. Petit's side have found the back of the net on a meagre six occasions, meaning they have by far the worst attacking figures in the Primeira Liga.
If Belenenses want to maintain their top-flight status this year, then they are going to have to find a balance between being solid at the back and having enough intent going forwards.
Monday could be a good place to start, given they are coming up against one of the worst defences in the country.
Tondela have won two of their last three encounters, which has elevated them to 11th position.
Despite their mid-table status, Pako Ayestaran's side are only three points better off than their upcoming opponents, and a defeat in midweek could see them dragged back towards the drop zone.
As previously stated, their leaky defence has caused CDT Auriverdes issues in the current campaign. Tondela have conceded four goals on three separate occasions in 2020-21, and addressing those fragilities at the back will be pivotal to their future success.
The Estadio Joao Cardoso outfit will be full of confidence coming into this one after their recent results, though, and a win could see them looking up the table rather than nervously over their shoulders.
Belenenses Primeira Liga form: WLLDLL
Belenenses form (all competitions): WLDLWL
Tondela Primeira Liga form: LDLWLW
Tondela form (all competitions): LDLWLW
There have been several Portuguese clubs affected by a string of positive coronavirus results in recent weeks and Belenenses are one of those sides.
Tondela have also been heavily hit by positive test results forcing four of their first-team squad out of action.
Belenenses possible starting lineup:
Kritsyuk; Lima, Ribeiro, Silva, Phete, Esgaio; Edgar, Taira, Sithole; Cassierra, Cardoso
Tondela possible starting lineup:
Niasse; Bebeto, Medioub, Tavares, Suarez, Khacef; Murillo, Pedro, Augusto, Salvador Agra; Gonzalez
We say: Belenenses 0-2 Tondela
The two teams are fairly evenly matched, but Tondela are carrying some good momentum into this fixture, and that could prove to be the difference on the day.
Belenenses have seriously struggled in front of goal all season, and until those issues are solved, it is hard to see them escaping the relegation zone.