At the time, Davis lived in Illinois, where her father, former NBA forward Antonio Davis, had played for the Chicago Bulls. Both preteens were playing for their respective club teams -- Davis for the Chicago Ice, Nelson for the Atlanta Celtics -- at the 12U AAU Nationals in Rochester, Minn. The Celtics surged ahead 19-1, but the Ice stormed back to win by one point in overtime.
"We didn't think we were going to beat [Kaela's team]," Kristina says of the Ice, which also featured a young Morgan Tuck, who signed a National Letter of Intent with Connecticut this fall. "We were thinking it was going to be a blowout."
The close loss fueled Nelson's urge for a rematch. Davis made it easy for her when her family relocated to Atlanta later that summer.
As luck would have it, she and Nelson ended up as classmates at Greater Atlanta Christian (G.A.C.). They played together for two years until Davis moved to Norcross (Ga.) for high school.
But this time, attending different schools didn't make them instant rivals. Instead, they joined the same club team -- the Georgia Ice -- and won the 13U AAU Nationals together.
As a sophomore, Davis transferred to Buford (Ga.), where she once again found herself competing against Nelson, G.A.C.'s 6-foot-4 center, who is ranked 30th in the ESPNU HoopGurlz Super 60 for the 2013 class. But, as the No. 2-ranked player in the 2013 class, Davis, a guard, wasn't worried about going up against her friend.
Their teams met four times last season, including in the state championship, which Buford won 57-38.
"When we first played each other in high school, we made comments [like] 'I don't know about you, but I'm tired,' to keep it fun and non-competitive," Davis says.
Coming off its state title, Buford headed into this season with another dynamic duo: Davis and senior guard Andraya Carter, who, along with Davis, has verbally committed to perennial powerhouse Tennessee.
But after Carter suffered a knee injury that will likely sideline her through January, Nelson entered the picture, transferring to Buford during the summer. Thanks to their longtime friendship off the court and summertime success on it, she and Davis were able to pick up right where they left off.
"It helps having been through the highs and lows together," Davis said of having Kristina back on her side of the court.
"I think Kristina's one of those kids who's great at figuring out what her role is," Davis said. "Some games she needs to be Robin, but she's definitely one to not take crap from anybody. Will she have to step down at some point where she didn't maybe at G.A.C.? Yeah."
Davis is confident Nelson, who has yet to choose a college, will help carry Buford, which is currently ranked No. 12 in the POWERADE FAB 50. They get their first major test at the Nike Tournament of Champions Dec. 17-22 in Chandler, Ariz. The tournament features 20 nationally ranked teams in its top two divisions.
"Coach [Gene] Durden and everyone sees it in her," Davis says of Nelson's ability to play the leading role.
Nelson is just happy to be there.
"Our first meeting of the season," Nelson remembers, "when the coaches were doing introductions, [when they got to me] they just said, 'If you can't beat them, join them.' "
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Chris Hansen is the national director of prospects for ESPN HoopGurlz and covers girls' basketball and women's college basketball prospects nationally for ESPN.com. A graduate of the University of Washington with a communications degree, he has been involved in the women's basketball community since 1998 as a high school and club coach, trainer, evaluator and reporter. He is a member of the McDonald's All-American team selection committee. Hansen can be reached at firstname.lastname@example.org.