There were two clear-cut opportunities from both sides immediately after the break, starting with Aubrey Modiba’s thunderous left-footed shot clipping the crossbar with Stephens beaten.
Then Titus saw his clever curling shot from the outside of the boot go just wide of February’s upright.
There was a moment of drama in the 58th minute when referee Thokozani Mkhize awarded Stellenbosch a penalty after Grant Kekana hacked Titus in the box despite fierce protests from Sundowns’ players.
Basadien showed nerves of steel to stand up and send February the wrong way as Stellenbosch took the important lead.
To try to catch up with the game, Mngqithi and his technical team rang changes, the most notable one the introduction talismanic midfielder Themba Zwane for Modiba after in the 72nd.
Zwane made an immediate impact as his introduction injected some life into Sundowns as they began to attack the Stellenbosch defence but they could not find the way past Stephens and his back four.