It's hard to say who was more upset, Illinois junior guard D.J. Richardson and his teammates or the United Center crowd.   No. 19 Illinois rolled into the city with 10 straight wins and a top 25 ranking, but UNLV double-teamed Illini big man Meyers Leonard and harassed the Illini guards while pulling away for a 64-48 win over the Illini in a non-conference basketball game Saturday.
  Tentative to start, the Illini were glassy eyed after losing before a crowd of 15,144 fans in the United Center -- the home away from home -- for the third consecutive game and fifth time in the last six appearances here.   "This is my third year up here,'' said Richardson, who scored a game-high 19 points. "I'm 0-3. It's tough. Third time coming up here and laying an egg. We wait too long to try to fight.  Hopefully, we can get it next year.''   The alums weren't too pleased, and they booed the Illini before starting to file out with 2 minutes 10 seconds left. It's only one loss, but the Illini failed to provide any evidence of improvement, a deep bench or the ability to score and rebound against an athletic opponent.   "Obviously, we're very disappointed to be 10-0 and maybe a little bit of a surprise, then maybe not dealing with success,'' Illinois coach Bruce Weber said. "Some days are like this. It's just sad it happened here today. It's a great chance to capitalize on being up here with recruits and fans and gaining support.   "It was more Vegas than the building.''   The Illini fell to 10-1 before hosting Cornell at Assembly Hall Monday (7 p.m., no TV). The game against No. 10 Missouri is Thursday in St. Louis.   "We've talked for a week here, 'Are we getting better?' '' Weber said. "The competition is obviously getting better. We didn't rise to the challenge.''   UNLV is Missouri-lite.   "They're both very explosive at scoring the basketball,'' said Illini guard Sam Maniscalco. "That's the glaring similarity between them. We have to learn from this game.   "(UNLV) came out swinging. We didn't punch back. Obviously, we didn't show up and play well.''   The Runnin' Rebels doubling down on Leonard, who entered as the team's leading scorer but had seven points on 3 of 8 shooting. He also made only one free throw in six attempts. UNLV was determined not to let him win the game.   "He's a tremendous player, a lottery pick type of player, without question,'' said UNLV coach Dave Rice. "We didn't want him to get going early.'' That kind of talk might have clouded Leonard's head over the past couple weeks, Weber said.   "All the stuff about the NBA, where he is and where he is going . . . it's just too much for him right now,'' Weber said. "He's got to be a good college player. When he becomes a good college player, then he'll have his chance to be in the NBA. It's going a little fast for him. Maybe this will be good. He'll settle down, get to practice and get better.''   While it wasn't one of Leonard's better games, it might have been the worst from everyone else, except for Richardson, who was 5 of 8 from the 3-point line but just 6 of 17 for the game.    Maniscalco and guard Brandon Paul combined for 3 of 22 from the field, and forward Tyler Griffey didn't take advantage of matchups against guards when UNLV concentrated on Leonard.   The Illini shot 25.4 percent from the field and just 22.9 percent in the second half with eight air balls, when they didn't react to UNLV's switching defense and the Illini became stagnant.   Illinois trailed by 15 before rallying within 54-46. After a timeout, the Illini could only manage a 25-foot airball from Maniscalco just before the shot clock. The crowd booed, then got up and left a few seconds later with 2:10 left. The Illini had a deer-in-the-headlights look.   UNLV (11-2) avenged a 73-62 loss to the Illini in the NCAA Tournament last season after falling by 11 points at Wisconsin last weekend.   "I was asked all week about the NCAA Tournament game,'' Rice said. "I didn't feel that was a big part of the motivation. The bigger thing was our guys were frustrated with the effort last week (at Wisconsin).''   Maybe the Illini can learn a lesson.   John Supinie can be reached at Johnsupinie@aol.com. Follow him on Twitter @JohnSupinie.   Illinois report card Front court -- D The Illini didn't get much done inside. UNLV kept doubling down on Meyers Leonard, and Tyler Griffey didn't do much to keep them honest. Back court -- F The Illini starting guards were 9 of 39 from the field. This place used to be a homecourt advantage. Bench -- F There was little productivity from the bench. Only Crandall Head played more than 7 minutes. Overall -- D Against a team that beat then-No. 1 North Carolina on Thanksgiving weekend, Illinois came out tentative. This was no way to entertain the folks in Chicago, and UNLV is Mizzou-lite.