Williams, who missed the first four games of the season due to injury, posted his second straight double-double. Also posting double figures in scoring was Elijah Millsap and Larry Owens with 15 each and Jerome Dyson with 10.
The Legends were led by Sean Williams and Dominique Jones with 19 and 18 points, respectively.
Texas took advantage of 51 trips to the free throw line, connecting on 43 (.843). Tulsa outrebounded the Legends by a 37-34 margin in the first meeting between the two teams in D-League history.
The 66ers will return to Tulsa to take on the Rio Grande Valley Vipers on Sunday, Dec. 5 at 4 p.m. inside the Tulsa Convention Center. It will mark their third back-to-back set of the season and the first time matching up with RGV since the 2010 D-League finals last season.