Christmas, averaging 21 points, hit nine of 13 shots, including all five his shots from 3-point range. Williams, a 6-foot-9 sophomore, shot 6-for-12, including 5-for-10 from long distance.
The Owls (9-6) shot 13-for-19 from 3-point range.
Temple made five of six 3-point shots in the first eight minutes and sped to a 25-7 lead. Penn reserve guard Harrison Gaines then scored eight points during a 10-0 run. But Christmas hit a 3-pointer that sparked a 15-5 spurt, and the Owls moved out to a 42-24 halftime advantage.
Temple opened the second half with a 16-7 run for a 58-31 lead, and was up by 30 points three times.
Seton Hall sophomore Isaiah Whitehead will stay in the NBA draft and not return for his junior season.
Washington State's trio of Josh Hawkinson, Conor Clifford and Ike Iroegbu have withdrawn from the NBA draft and will play their senior season with the Cougars.
Gonzaga center Przemek Karnowski, who missed most of last season with a back injury, says he is returning for another year.