Despite a slow start and a compact defence from Sekhukhune, Sundowns found their rhythm and nearly took the lead on the 11th minute, with Neo Maema's low volley forcing goalkeeper Badra Ali Sangare into a save.
The visitors had another chance to take the lead on the half-hour mark, but Shalulile was unable to connect well with a cut-back from Sifiso Ngobeni, scuffing his shot into the hands of Sangare.
Both teams had opportunities before half-time, with Thapelo Morena missing a chance to score for Sundowns, but it wasn't until six minutes into the second half that the deadlock was broken, with Shalulile getting his ninth league goal of the campaign, deflecting Gaston Sirino's shot past Sangare.
As the game slowed down, Sundowns made several changes to refresh the team, but Sekhukhune were still determined to get back into the game, with Elias Mokwana coming close to levelling the score on the hour-mark, but goalkeeper Denis Onyango kept his first-time shot out.
Sundowns were forced to play the last 16 minutes with ten men after Marcelo Allende received a red card for a dangerous tackle on Victor Letsoalo, but the sending off did not affect the team, as substitute Mailula doubled the lead six minutes later, taking his tally to six league goals.
With this victory, Sundowns extended their winning streak to 14 matches and pulled 22 points clear at the top of the DStv Premiership, while Sekhukhune's four-game winning streak came to an end.