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.
South Carolina AD Ray Tanner is not "100 percent sure" Saturday's game vs. No. 7 LSU will be played at Williams-Brice Stadium because of devastating floods that hit the state.
UCLA junior linebacker Myles Jack has withdrawn from school and will enter the NFL draft, making the decision just weeks after suffering a season-ending knee injury.
A judge has dismissed simple assault charges against Rutgers wide receiver Leonte Carroo after the woman he allegedly attacked after a football game said she didn't want to testify.
Auburn senior receiver D'haquille Williams has been dismissed from the team.
Colorado coach Mike MacIntyre said he was sorry for getting into a sideline altercation with an assistant coach during a 41-24 loss to Oregon over the weekend.
Alabama coach Nick Saban took exception with the media's outlook on his team prior to Saturday's win at Georgia, lashing out at those who "buried" the Crimson Tide.