About the only thing Marquis Addison did wrong Wednesday night was pick up three fouls in the opening minutes of the second half.

Addison fired in a career-high 34 points, and Stephen Atkinson and Cameron Cornelius combined for another 34 to spark Missouri Southern past Pittsburg State 87-80 in front of 2,757 fans at the Leggett & Platt Athletic Center.

Addison, 6-foot-4 junior guard, popped in 23 points in the first half to lead the Lions to a 42-37 lead. He drilled 4-of-5 shots from 3-point range, 8-of-12 overall from the floor and all three free throws.

“I really put a lot on my shoulders, coming out and bringing some energy, and my teammates really fed off that,” said Addison, who also had four steals in his 26 minutes. “I was just hot. I got a couple of open looks to start the game, in-rhythm shots and those are big for myself. Making the first couple of shots really gave me some confidence. Players stepped up other than myself, and that was huge in the second half.”

Addison quickly found himself on the bench after picking up three fouls in the first 2:19 of the second half — the last two coming just 32 seconds apart.

“I was really second-guessing myself after not taking him out after the third foul,” Lions coach Robert Corn said. “A veteran player, you usually leave them in a little longer. But when he picked up his fourth, our guys could have folded the tent. We didn’t waiver a bit. Our guys still had confidence and battled through things. ‘Cam’ came in and really did a great job.”

Cornelius entered and contributed seven points in a four-minute stretch — the first three on a 30-footer from in front of the Lions’ bench to beat the shot clock for a 54-45 lead with 14:13 left.

“I’m thinking just get a shot up and hit the rim,” Cornelius said with a grin. “I’ve hit that in practice, and I’ve always heard the way you practice is the way you play. You do it in practice, and if the moment comes (in a game), why not try it.”

The Lions (9-5, 4-2 MIAA) maintained a 4-9 point lead for most of the 10 minutes that Addison was on the bench. But the Gorillas ran off six quick points — two free throws and a layin by Rico Pierrevilus and a tipin by Denton Hays — to pull within 63-61 with 7:42 to play.

Addison re-entered at that point, and he hit a 17-footer and two free throws within two minutes to give the Lions a 71-66 lead with 5:29 left.

Moments later, Atkinson  made a reverse layup, a short jumper and two  charities during an 8-2 run that gave the Lions a 79-72 lead with 2:43 remaining, and the Gorillas never got closer than five points the rest of the way.

Addison finished 10-of-14 from the floor and 10-of-10 at the line for his 34 points, one more than he scored in last season’s 96-92 double-overtime home victory over the Gorillas.

“He got us out of the gate and really carried us in the first half,” Corn said. “He came out really assertive and aggressive, and his shot was falling for him.”

“Every time we made a run, they had an answer, and Southern’s biggest answer was Marquis,” Gorillas coach Kevin Muff said. “He was really good tonight, not just scoring the ball but the pace of his game, involving other players. He’s a good defender, too. We knew coming in he would cause us some problems, and having 23 points in the first half, give him credit and our defense has to be better.”

Atkinson, a sophomore, netted 13 of his career-best 21 points in the second half, going 7-of-12 from the field and 6-of-6 at the line.

Cornelius also set a career high with 13 points, hitting 3-of-3 fielders and 6-of-9 free throws.

Jordan Talbert just missed a double-double with nine points and 10 rebounds, and he blocked four shots, the last one with a minute left.

“Jordan’s play at the end was really a big play — a block, and able to get the ball out for two free throws at the other end,” Corn said. “I thought everybody played well and everybody contributed.”

Pierrevilus, 6-7 senior, scored 21 points and grabbed 12 rebounds — seven off the offensive glass — to lead the Gorillas (11-4, 4-3). PSU outrebounded the Lions 44-33 and had 21 offensive rebounds, leading to 15 second-chance points.

“Rico was great,” Muff said. “He was very active on the boards. He did a great job of keeping a lot of balls alive. He got to the free-throw line (hitting 9-of-9 attempts).”

JaVon McGee had 19 points and nine rebounds for the Gorillas, and Courtney Ingram and Nolen added 12 and 10 points, respectively.