Two goals from magic man Lee Trundle sent the Swans three points clear of Huddersfield ahead of Saturday's fixtures.
He netted from the spot in the 25th minute and then clinched a deserved victory midway through the second half.
The Swans were unchanged from the side that beat Southend, so once again skipper Roberto Martinez had to be content with a seat on the bench.
A poor final ball let the Swans down until Trundle popped up in the 15th minute to cross into the danger area but Terry Skiverton headed behind for a corner.
The Swans went ahead in the 25th minute when Kevin McLeod sent a long ball out of defence which Trundle latched on to and, after being felled by Efe Sodje, he notched his 16th goal of the season from the spot to put the table-toppers deservedly ahead.
Willy Gueret and Izzy Iriekpen collided as the keeper came out to collect a high ball. With both players on the ground, Yeovil carried on playing until the referee was forced to call a halt so that both players could receive attention.
Eight minutes into the second half, Yeovil were down to 10 men when Lee Johnson was dismissed. He was yellow carded for a foul and then gestured at referee Keith Stroud who promptly showed him another yellow followed by a red.
Three minutes later Trundle had the ball in the net but was flagged for offside.
Yet another piece of Trundle magic settled the match in the 67th minute.
Chris Weale cleared the ball under challenge from Adebayo Akinfenwa and it went straight to Trundle, who, although being 35 yards out, sent the ball into the back of the net past a motionless keeper.
The goal settled the Swans down and although the Glovers went looking for a consolation score, the home defence stayed firm to earn a deserved victory.