McCombs rushed for 94 yards and his fourth-quarter touchdown. McCummings, who also came in at quarterback occasionally, ran for a 3-yard score that gave the Huskies a 14-0 first-half lead.
That came after Williams scored the game's first touchdown on a 58-yard punt return.
Connecticut (2-1) started quickly in going against their former coach, Randy Edsall, who left after 2010 to come to Maryland (2-1). Both sides spent much of the week downplaying talk of any hard feelings.
The Huskies outgained Maryland 148-80 in total yardage in the first half and controlled the ball for 18 minutes, 40 seconds. They also came up with timely plays, converting four of nine third-down situations to keep the Maryland offense off the field.
Connecticut opened the scoring on Williams' 58-yard punt return, and Chad Christen's extra point gave the Huskies a 7-0 lead with 7:05 left in the first quarter.
They took advantage of a short field to score their second touchdown, gaining possession at the Maryland 36 after the Terrapins were forced to punt from their 4. McCummings' 3-yard run seven plays later made it 14-0 with 12:35 left in the half.
Connecticut linebacker Yawin Smallwood sacked Hills and forced a third-quarter fumble that Angelo Pruitt recovered for the Huskies at the Maryland 23. They couldn't pick up a first down, but Christen kicked a 34-yard field goal with 3:29 left in the quarter for a 17-7 lead.
Smallwood caused problems for the Terrapins throughout the game, with four of his 14 tackles going for losses, including three sacks.
After a 75-yard drive, Maryland made it 17-14 on the second play of the fourth quarter when Hills threw a 29-yard touchdown pass to Diggs on third-and-10. The Terrapins' Marcus Leak tipped the pass and Diggs grabbed it for a touchdown to make it 17-14.
But the Huskies answered on their next possession, driving 76 yards to take a 24-14 lead on McCombs' 11-yard touchdown run.
Hills ran for a 10-yard touchdown that cut the Connecticut lead to 24-21 with 4:39 left.
After getting the ball back following a Huskies punt, Maryland reached the Connecticut 39 before its drive stalled with 17 seconds left.
Texas Tech has 665 yards of total offense in its 48-45 victory over Texas.
DeAndre Washington ran for 173 yards and two touchdowns and Texas Tech overcame a breakout performance from Texas freshman tailback Chris Warren III as the Red Raiders beat the Longhorns 48-45 Th
Texas Tech outlasts Texas in a wild Thanksgiving game that included a fake kneel down for a touchdown.
The Red Raiders lined up like they would kneel the ball and run out the clock against Texas. Instead, Jakeem Grant surprised everyone, scoring from 40 yards out.
Quinton Flowers passed for three touchdowns and ran for two more as South Florida routed Central Florida 44-3 Saturday night.
South Florida defeats UCF 44-3 to drop the Golden Knights to 0-12 on the season.