Miller, the 6-foot-9 freshman forward, had 20 points and has led the Bears (3-0) in scoring in all three games this season. Acy, a senior, had 13 points.
The game was tied at 32 early in the second half before the two Quincys put the Bears out in front with an 18-5 run.
|More on SDSU-Baylor|
Miller, a 6-foot-9 forward, had 20 points and has led the Bears in scoring in all three games this season. He had seven points in that five-minute spurt early in the second half, while Acy scored nine of his 13 points during that stretch.
"Acy is the backbone of this team in my opinion. He's a four-year veteran. He only cares about winning. Miller is terrifically talented," San Diego State coach Steve Fisher said. "They've got a nice blend of youth and age and experience and that's why they're a good team."
After a pair of 17-point efforts his first two college games, Miller had five points and three fouls that limited him to eight minutes in the first half. Like his first two games, he was strong after halftime, even in foul trouble for the first time.
Baylor coach Scott Drew said he was impressed with the way Miller was able stay aggressive and avoid picking up more fouls.
The game was tied at 32 before Miller put the Bears ahead to stay with his inside jumper with 16:49 left, then made two free throws less than a minute later.
After Chase Tapley made a jumper for the Aztecs (3-1), Acy made three free throws in an eight-second span before his momentum-turning play, when he drove the baseline around 6-11 Garrett Green and under the basket before reaching back for a rim-rattling slam.
"I just try to provide that spark whenever I can. Whenever I get around the rim, I'm just looking to break it," Acy said.
"Oh, man! Q Acy's dunk started it all," Miller said. "He got me so hyped."
Tapley had 28 points while hitting eight of 10 3-pointers to lead San Diego State, which played its fourth game in five days and had 21 turnovers -- the same as Baylor.
"I don't think fatigue was a factor. I think Baylor was a factor," Fisher said. "Their length and their athleticism took away what looked like could be baskets a little bit like we did last year."
Miller followed the dunk with three free throws before Heslip's long jumper put Baylor up 46-34 with 13:22 left.
Tapley then made a 3-pointer before Acy hit two free throws and had another inside basket to make it 50-37.
Heslip had 16 points with four 3-pointers for Baylor, while Anthony Jones had 11 points.
Baylor played the third of five games to start the season without suspended sophomore standout Perry Jones, a 6-foot-11 forward who was the Big 12 preseason player of the year. He is serving an NCAA suspension for accepting improper benefits before he got to Baylor.
Jamaal Franklin had 11 points for San Diego State, while Xavier Thames and James Rahon had 10 each.
This is not the same San Diego State that last season won 34 games and went the NCAA round of 16 under coach Steve Fisher.
Tapley is the only returning starter for the Aztecs, the back-to-back Mountain West Conference champions.
The Aztecs opened with three games at home over the weekend, winning easily over Bryant, Southern Utah and UC Davis. This was a different challenge, and Baylor scored 17 points off turnovers, 10 more than San Diego State - the final point differential.
The rare midweek afternoon game was part of ESPN's tipoff marathon.
It was San Diego State's second visit to the Ferrell Center. The Aztecs were the first opposing team to play in the building, beating the Bears 83-58 on Nov. 29, 1988. The two teams had last met in an NIT semifinal game in March 2009, a game the Bears won 76-62.