The Marquette guard's cousin Derek is an Army officer on a Patriot missile unit in the war in Iraq.
"That's life and death over there," Diener said. "And this is a meaningless game of basketball."
Derek played the sport for two years at Army before graduating in 2000. He was stationed in Saudi Arabia last year and called his family, including younger brothers who play for DePaul and Saint Louis, this month to say he was on the move. He couldn't say where.
"I think about him all the time," Diener said.
The NCAA men's basketball field was dotted with coaches and players who have personal connections to the war.
IUPUI's Matt Crenshaw served in the Navy before college, and he knows several Marines who are in Kuwait. They e-mailed him before the tournament, urging him to concentrate on the court not the combat. He couldn't, of course.
"You really can't focus in on basketball too much," he said.
Creighton forward Kyle Korver's mind was on his high school pal Jeff Mishler, serving in the Army in the Middle East.
"People talk to me about pressure. If I mess up tomorrow, so what, big deal. If he does, he could die," Korver said before the Bluejays lost to Central Michigan.
For Pittsburgh forward Donatas Zavackas, a 22-year-old senior from Lithuania, the war brings back memories of when he was 11 and watching footage of unarmed countrymen facing tanks when Lithuania gained its independence from the Soviet Union in 1991.
Duke coach Mike Krzyzewski is a West Point graduate and a former Army captain. He said soldiers overseas want to know that nothing has changed back home. It makes sense that the NCAA tournament is going on uninterrupted, he says. March Madness providing a small escape from the madness of the world.
Playing and patriotism go hand-in-hand, Wisconsin coach Bo Ryan said.
"The government has their obligations to protect us. Our players have athletic scholarships and are students athletes here," Ryan said. "So obligations are being fulfilled on both ends."
Thanks to Diener, Marquette is in the NCAA regional semifinals for just the second time since Al McGuire led the school to its only national championship in 1977.
Wouldn't it be something if Diener could lead the Golden Eagles all the way to the Final Four?
"Sure," Diener said. "Our goal from day-one has been to win the national championship. But what I really want is for our troops to get home safely."
Without Diener's unshakable leadership and 55 points in two games, Marquette wouldn't be preparing to face Pittsburgh in the Midwest Regional on Thursday.
The sophomore point guard never had consecutive 20-point games before pouring in a career-high 29 against Holy Cross and 26 against Missouri.
While teammates Dwyane Wade, Todd Townsend, Robert Jackson and Scott Merritt have struggled at times in the first two games, Diener is tied for the tournament scoring lead.
Diener dedicated the victory over Holy Cross to his cousin in the battlefield, saying: "I hope for a few minutes that I can bring excitement to him."
He feels funny getting all the accolades for his basketball skills while troops march toward Baghdad.
"They are the heroes in our lives," he said. "They deserve more recognition."
And their loved ones merit a diversion, too, he said. Diener's family has welcomed Marquette's run as a needed respite.
"The two and half hours that I'm playing, I take their minds off that and bring enjoyment to them. That's what I'm trying to do," he said.
"I think basketball as a whole is doing that for the nation."
By Arnie Stapleton