The 22-year-old found the back of the net twice in the first half at Stade Pierre-Mauroy to help Christophe Galtier’s men escape the drop to Ligue 2.
Coming into the game, Lille needed a win to retain their Ligue 1 status in a season afflicted with poor result, and it looked like they were destined for relegation when Dijon took a shock 11th-minute lead through Chan-Hoon Kwon.
However, the young South African levelled matter seven minutes later thanks to an assist from Kevin Malcuit.
Malcuit, again, was the provider as the South African completed his double in the 33rd minute as Lille took led going into the halftime break.
In the second half, Dijon fought back but Lille held on to secure maximum points to ensure safety.
Mothiba was on parade from start to finish and took his goal tally to five in the French elite division.
Lille travel to the Stade Geoffroy-Guichard for a date with eighth-placed Saint-Etienne in their last game of the season.