Siwelele, who will today have new coach Veselin Jelusic in charge for the first time, host Steve Komphela's side at Free State Stadium.
The 2016/17 season is one they will want to quickly forget after battling the threat of relegation throughout the campaign.
Mahlasela was one of the shining lights for Celtic in an otherwise dismal campaign and his performances even attracted attention from today's foe, Chiefs.
Interest in the former Royal Eagles midfielder has seemingly cooled, and Mahlasela is fully focused on starting the season strongly with Celtic.
"Playing against Kaizer Chiefs in the first game of the league is a big thing and I've said before it is motivation on its own," Mahlasela tells KickOff.com.
"So we're looking forward to the game and probably if we win it'll give us a huge boost going into the next game. I can assure you we are going to give it our best shot on the day.
"The mood is fine in the camp as we are playing against Kaizer Chiefs and Kaizer Chiefs is a big team.
"I think everyone, when playing against a big team, you naturally become motivated, and playing against Chiefs is motivation on its own. We're under no illusion that it will be a tough game but we're looking forward to it."
Celtic have looked to rectify last season's poor showing by bolstering the squad with the likes of Roggert Nyundu, Ndumiso Mabena, Jacky Motshegwa and Victor Letsoalo.
"One thing I can tell you is that we've got a good bunch of players, we've got a great team and we are going to fight so that what happened last season doesn't happen this season again," Mahlasela reveals.
"Last season we were out of the top eight and we want to make sure that when the season finishes we are in the top eight.
"We are just going to keep on fighting. Each and every game we take it as a cup final and see where we end up."