Thomas had 14 points and 10 rebounds in the first half to help the Lady Bulldogs (7-2) take a 33-17 lead.
Angie Ball added 19 points for the Lady Bulldogs, who got just 13 points from the rest of the roster.
Overall she helped the Lady Bulldogs achieve an 86-12 record overall during her collegiate career.
Her twin sister, Coco, scored 18 for the Lady Bulldogs.
One of the earliest strides for the Lady Bulldogs came in 1986.
The squad used depth to win the crown as the Lady Bulldogs' 800 freestyle relay team was the only event winner.
The Lady Bulldogs have shown marked improvement over the last decade.
The women's basketball team is known as the Lady Bulldogs.
The Lady Bulldogs never led until Roundtree hit two free throws with 7:51 left in the game for a 70-68 advantage.
Union's teams are known as the Bulldogs and Lady Bulldogs.