Scheyer scored 22 points, Smith added 19 and the Blue Devils became the latest Top 10 team to beat Long Beach State, routing the 49ers 84-63 on Tuesday night.
Kyle Singler added 14 points for Duke (10-1), which led by 26 points, shot 47.1 percent, blocked a season-high 10 shots and was 15 of 26 from 3-point range.
"I don't even think we shot as well as we could, with the amount of good looks that we had," Scheyer said. "We'll be successful in the offense when we take open looks."
Larry Anderson scored 14 points for Long Beach State (6-7), which couldn't get closer than 13 points in the second half and lost its third straight. The 49ers have been beaten by four Top 10 opponents so far.
"I'm glad we're hitting league [play] on Saturday," coach Dan Monson said. "The Top 10 is pretty good, and Duke belongs there. ... Our guys could have caved in, and they showed that they've been in these games and that they have some fight to them, but we were just outmanned."
Senior big men Lance Thomas and Brian Zoubek had 10 points apiece for Duke, which went up by double figures to stay before the 49ers made their third field goal and went on to win its fourth straight while showing little rust from the nine-day holiday layoff that followed a 35-point rout of then-No. 15 Gonzaga.
"Guys over the break, nobody took any days off," Smith said. "Everybody stayed in shape, stayed sharp with their shooting or whatever they were doing."
It showed -- especially in the backcourt of Scheyer and Smith.
After combining for 44 points against the Bulldogs, they led the way again. Scheyer had his third straight 20-point game, and he and Smith were a combined 15 of 32 from the field with 10 3s, 14 assists and no turnovers between them.
It showed, and it helped them extend a few streaks at Cameron Indoor Stadium. Duke -- which had only one previous home game decided by fewer than 25 points -- has won 75 straight nonconference games at Cameron, 35 in a row here against unranked teams and 48 straight at home in December.
This one probably came with a bonus for the Blue Devils: a boost to their RPI and strength-of-schedule numbers, which will carry even more weight in a few months when the NCAA tournament selection committee gets together.
According to one unofficial online replication of the RPI formula, the 49ers have played the nation's toughest schedule. They previously lost to No. 2 Texas, No. 3 Kentucky and No. 6 West Virginia by an average of 23 points and failed to keep it closer than 13 against any of them.
"I think [Duke is] every bit as good [as those other Top 10 teams], but that's what everybody asks me when you're going on this Washington Generals tour," Monson said. "Everybody knows that none of these teams are good enough to win a national championship right now. ... It's all a matter of who keeps improving in the next two months, because they all have the ability to do it."
Long Beach State was coming off an 86-73 loss to Kentucky in which the 49ers were tied at halftime, but this time, the Blue Devils tried to take them out of the game much quicker.
"They weren't in awe of anybody, and they weren't going to back down," coach Mike Krzyzewski said.
Duke used a 27-7 run to build a 27-9 lead, with the burst highlighted by two 3s from Scheyer and an impressive display of athleticism from Smith -- who blocked Casper Ware's 3-pointer before hustling downcourt to take a pretty feed from Singler and hit a layup to push the Blue Devils' lead into double figures to stay.
That was just one in a bonanza of blocks for Duke. With 5 minutes before the break, Long Beach State had more shots blocked (seven) than made (five) -- and that helps explain why the 49ers managed just two field goals during a span of roughly 11 minutes.
"You've always got to start with defense, and the offense will come," Smith said. "But it started with defense. It sets a tone."
Conversely, there were times when the Blue Devils seemingly couldn't miss from long range.
Late in the half, six consecutive Duke field goals were 3s, including four in a 3 1/2-minute span and two 26 seconds apart by freshman Andre Dawkins that stretched the lead to 42-16 with just under 4 minutes left.
"The whole game, we were excited to play, but especially the first half [because it was the first game] in probably about 10 days," Smith said. "Everybody was excited, ready to get after this team, especially seeing the teams that they played. ... They played Kentucky tough. So we were definitely ready for this team, and we had to play a full game."