CHAMPAIGN, Ill. (AP) -- For 30 minutes against top-ranked Illinois, Longwood looked like a contender, not a team with only one victory this season.
The Lancers cut a 13-point halftime deficit to seven on Monday night and were down by only eight, 73-65, when the Illini finally buckled down with 9:13 to go.
"We knew we weren't playing with any energy, not playing hard, and they were just getting too many easy baskets," said Deron Williams, whose 3-pointer ignited a deciding 16-0 run to lead the Illini to a 105-79 victory.
The Illini (12-0) held Longwood scoreless for nearly four minutes and built their lead to 98-71 with three minutes remaining.
Williams led Illinois with a season-high 23 points and had seven assists. Offense wasn't a problem for the Illini, who got 20 points from Luther Head, 16 from James Augustine, 13 from Roger Powell Jr. and 13 assists from Dee Brown.
But defensively, coach Bruce Weber said his team left too much to chance.
"We've got to click it in defensively. That's what's made us No. 1," Weber said. "If we don't click it in defensively, we're not going to be No. 1 for very long."
Illinois couldn't stop Longwood's Michael Jefferson, who had a career-high 30 points. Four other Lancers scored in double figures and Longwood shot 53 percent from the field.
"We earned their respect," Jefferson said. "My teammates stepped up. Everybody stepped up, made big plays, played good defense, made some big shots."
The Lancers (1-14) are playing a full NCAA Division I schedule for the first time this season and the crowd of 16,618 was almost 16,000 more than they see at a typical home game. Illinois won its 38th in a row at Assembly Hall against non-conference opponents.
"This is extremely significant for our players, for our university," Longwood coach Mike Gillian said. "We've got some good players, they're great kids and they're going to give a lot of effort."
Weber said he "went off" on his team during Sunday's practice for its recent lack of defensive intensity, but he said now it's up to his players.
"I did my yelling last night," he said. "Now they've got to yell at themselves. They've got to take some pride."
The Illini got their toughest test of the season against Missouri last Wednesday before prevailing 70-64.
Powell's two steals in the first half keyed a 9-2 run that gave the Illini the lead for good. They built an 18-point advantage in the first half before Longwood closed the gap.
Both teams now head to Las Vegas for two games later this week as part of the Las Vegas Holiday Classic. Longwood meets Cincinnati (No. 17 ESPN/USA Today, No. 22 AP) and Valparaiso. Illinois faces Northwestern State on Thursday and Cincinnati on Friday.