Peter Shalulile netted a hat-trick while Surprise Ralani scored the other goal in the first half. Swallows got their goals from Dillon Solomons and Ruzaigh Gamildien.
The result took Sundowns to 54 points and they are still 11 points off second-placed Royal AM while Swallows still 15th with 18 points from 23 games.
Sundowns had a perfect start to the game with Shalulile firing them ahead with a header from a George Maluleka cross in the 10th minute.
Shalulile completed his brace after another pass by Maluleka who found the Namibian attacker with a defence-splitting pass.
Sundowns’ celebration was cut short as Swallows pulled one back barely a minute later as the misunderstanding between Lyle Lakay and Bradley Ralani gifted Dillon Solomons a goal.
Sundowns restored their two-goal cushion on the half-hour mark as Swallows failed to clear their lines and the ball fell for Ralani who fired past Thela Thela to make it 3-1.
And that’s how the first half ended, and Dylan Kerr knew he had a mountain to climb going into the second 45 minutes.