By the end of Tuesday night's taut Bulls-Mavericks meeting at the United Center, a Marquette alumni game had broken out.

When it ended, one former Golden Eagle had gotten the better of two.

Wesley Matthews' 3-pointer with 11.7 seconds left gave the Mavericks a 99-98 victory, allowing them to sweep the season series. The Bulls suffered a defensive breakdown on the play.

After a timeout, the Bulls let Jimmy Butler go to work, but Matthews knocked the ball away. It ended up in the hands of the patriarch of the current Marquette family tree, Dwyane Wade, celebrating his 35th birthday.

But Wade's potential game-winning shot went long, capping his 8-for-21 night.

“We wanted to give the ball to Jimmy at the top of the floor and create some space,” coach Fred Hoiberg said. “Wes did a nice job poking the ball away.”

Butler, who had given the Bulls a two-point lead with another dagger jumper with 22.8 seconds left, finished with 24 points, a season-high 12 assists and nine rebounds, falling one board short of his first triple-double this season.

“The first half, they were the aggressors and we made a lot of mistakes,” Hoiberg said.

For every step forward this season, there's often a lapse the next game. For every gritty road victory, there's a giveaway at home.

And so it goes as the Bulls continue to stumble along the line that is the very definition of average, falling one game below .500 after yet another head-scratching defeat.

The Mavericks entered the United Center just 5-16 on the road but exited it with six players in double figures, topped by Harrison Barnes' 20 points. The Mavericks used a small lineup featuring Dirk Nowitzki at center, which helped Robin Lopez score a season-high 21 points.

“I thought Robin was great,” Hoiberg said.

Both at Tuesday's morning shootaround and in his pregame remarks, Hoiberg talked about bringing Nikola Mirotic back slowly. After all, Mirotic lost roughly eight pounds as he missed four games battling the virus that has plagued the Bulls.

But come crunch time, Hoiberg couldn't help himself. Speaking to how critical Mirotic remains to the Bulls' fortunes, Hoiberg played him the entire fourth quarter to help with floor spacing.

Mirotic scored six points in 22 minutes.

“Don't leave him or he'll shoot your face off,” Butler said. “As long as he's taking the shots he's supposed to take, we have the confidence they're going to go in. We might be more confident than he is.

“When he's in a slump, we want him to continue shooting the ball — that's what you do. So, yeah, I think if he stays in the gym, it's only going to come easier.”

Mirotic isn't the only Bull with questions about consistency. Doug McDermott, who scored a career-high 31 points Sunday in Memphis, failed to build off that as he managed just seven on 3-for-10 shooting.

“We were coming off one of our better performances of the year in Memphis,” Hoiberg said. “We just made too many mistakes. You have to play 48 minutes in this league.”

The Mavericks embarrassed the Bulls by 25 points in Dallas last month. This final score was closer but not much easier to swallow.

kcjohnson@chicagotribune.com

Twitter @kcjhoop