Gardner scored 21 of his career-high 28 points in the second half, leading Marquette to a 66-56 victory over DePaul on Saturday.
Golden Eagles coach Buzz Williams leveled a mild criticism of Gardner during the week for being lackadaisical at practice, but started the senior forward for the first time since Jan. 28, 2012 at Villanova, in place of junior guard Derrick Wilson.
"I did give him the start even though he hadn't earned it, and I took it away from Derrick, and Derrick had earned it," Williams said.
Williams started Gardner over Wilson to get all four of his seniors in the lineup. The Golden Eagles (9-6, 1-1 Big East Conference) were ranked 17th in the Associated Press preseason poll and were picked to win the Big East in the preseason coaches' poll, but have stumbled to open the season.
"If it can't be your seniors to take ownership, who will it be?" Williams asked rhetorically.
Gardner acknowledged that he was not working hard enough at practice, but was told Friday he would be starting anyway.
"I have been slacking a little bit in practice," Gardner said.
"Since we came back from Christmas break I've been out of it, but I think I'm back in rhythm," he said.
He sure looked in rhythm against DePaul. With Gardner leading the way by making 10 of 11 free throws, the Golden Eagles made 23 of 31 free throws to DePaul's two of four.
The disparity in free throw shooting had Blue Demons coach Oliver Purnell upset.
"I'm a little miffed we didn't go to the line a little more," Purnell said. "I thought we were driving the ball in there pretty hard and just weren't coming up with anything. But that's the way it is on the road in the Big East."
Cleveland Melvin snapped a three-game slump by scoring 22 points for the Blue Demons (8-7, 0-2). Brandon Young, DePaul's second-leading scorer at 14.4 points, missed all nine of his shots and was held scoreless.
The Golden Eagles used a 14-2 run late in the second half to take control of the game, with Gardner scoring the final seven points of the streak.
"Gardner gave us all kinds of problems and we really didn't have an answer for that," Purnell said. "Turnovers absolutely killed us the last seven (or) eight minutes of the game.
"We turned the ball over five or six times in our half-court offense on critical possessions," he said. "We just can't afford to do that."
Jamil Wilson had 14 points and Todd Mayo added 10 for Marquette.
Billy Garrett, Jr. was the only other DePaul player in double figures, scoring 10 points.
Gardner's previous high at Marquette was 26 points in a 74-71 win over Syracuse on Feb. 25, 2013.
After the game, he said he had no preference whether he started or came off the bench.
"It really don't matter to me, as long as I come in the game and contribute," he said.
Melvin averaged 17.6 points in DePaul's first 11 games this season, but had struggled in the team's past three contests, averaging only seven points on nine of 32 shooting.
Melvin scored 15 points and DePaul led, 30-26, at halftime.
"(The Golden Eagles) were just trying to find a way to stop me, because I was hot," Melvin said of scoring only seven points in the second half. "Obviously they did a good job of that. But still I was trying to compete out there and win the game."
Freshman center Tommy Hamilton IV, who had started the team's first 14 games and was averaging 9.2 points, did not play the first half. Hamilton was held scoreless with no rebounds and accumulated four fouls in just six minutes.
Purnell said he benched Hamilton to send him a message that he had to work harder and needed to be ready to start at the beginning of games. He also said junior forward Jamee Crockett, averaging 3.8 points, had been suspended for the Marquette game for "conduct unbecoming" of a player.
He said Crockett would return to practice in the coming week.