The league leaders made a crucial return to winning ways last time out, as they defeated strugglers Farense 1-0, while Belenenses continued their rise up the table with a 2-0 victory over Maritimo.
Sporting Lisbon picked up an important victory on Friday, as Pedro Goncalves fired them to a 1-0 win away at Farense.
That followed a slightly concerning week for Ruben Amorim's men, as they dropped points with two consecutive draws to Moreirense and Famalicao.
Despite that, Os Leoes do sit six points clear at the top of the Portuguese top flight, having gone unbeaten in the league so far this season, although Porto do remain in hot pursuit in second place.
Their position at the summit of the table is largely down to their solid defensive record, with no other side in the top flight conceding as few as the 13 goals that Amorim's men have shipped in 27 league matches.
Meanwhile, only second-placed Porto top their tally of 49 goals at the other end of the pitch, showing that the side from Portugal's capital have built a balanced side this season.
As we approach the end of the season, Os Verde e Brancos will firmly have their sights set on securing their first title since 2002, and they will know that five wins out of their last seven matches will all but seal the title, even if Porto manage to win all their remaining matches.
They will look to tick off one of those victories on Wednesday, as they welcome a revitalised Belenenses side to the Estadio Jose Alvalade.
The visitors have hugely boosted their survival hopes in recent weeks, picking up eight points from their last five matches to lift themselves up to 12th spot.
As a result of their upturn in form, Petit's side now sit six points ahead of Maritimo in the relegation playoff place, and eight points above the automatic drop zone, having previously been involved in a heated battle for survival.
With plenty of points left to play for in a tight bottom half of the division, O Belem will be wary of taking their foot off the gas, and Petit will want to ensure that they continue to pick up points until the end of the campaign.
Wednesday's game presents a very tough obstacle though, as they travel to take on the league leaders who are yet to lose in league action this season.
Sporting Lisbon could remain without centre-back Zouhair Feddal, who missed the Farense victory through injury.
However, they did welcome young defender Goncalo Inacio back from injury last time out to strengthen the back line.
Amorim has started to change the shape of his side in recent weeks, most recently opting to deeply Paulinho and Pedro Goncalves as a front two.
In that game, Pedro Goncalves found the net to take his tally to 17 league goals in his first season in Lisbon, while the former Famalicao attacker has also set up four goals for his teammates.
He may opt to revert to the more usual front three for Wednesday's game, as they take on a Belenenses outfit who are known to be built on a defence which is particularly difficult to break down.
Petit could look to deploy the same side that picked up the 2-0 victory over Maritimo last time out.
However, Sphephelo Sithole will be pushing for a return to the starting side, after he served a suspension in that game.
Sporting Lisbon possible starting lineup:
Adan; Inacio, Coates, Reis; Porro, Palhinha, Mario, Mendes; Goncalves, Paulinho, Santos
Belenenses possible starting lineup:
Kritsyuk; Esgaio, Ribeiro, Henrique, Silva, Lima; Varela, Taira, Sousa, Cardoso; Cassierra
We say: Sporting Lisbon 1-0 Belenenses
While Belenenses will certainly prove a tough test for the league leaders, we see Sporting Lisbon coming out of Wednesday's game with a narrow victory to maintain their lead at the top of the table.
The visitors have definitely shown signs of improvement recently, but we would expect them to fall just short to a strong Sporting Lisbon side at the Estadio Jose Alvalade.