When Kansas University freshman Kim Karfonta checked into Sunday’s soccer game against Oklahoma, she was met by a familiar face.

Maybe too familiar.

The player she guarded was her sister Kirstin, a sophomore defender for the Sooners.

“It wasn’t that awkward,” said a grinning Kim after KU’s 2-1 loss to OU on Sunday. “A lot of people thought it was going to be a big deal, but we were just playing soccer.

“It was definitely fun.”

The two are used to seeing each other on the soccer field  they were teammates at Edmond (Okla.) North High School. They even played against each other on club teams.

In fact, Sunday’s biggest challenge might have been for the Karfontas in the crowd.

Kim and Kirstin’s mother, Kathy, and father, Dick, two grandparents and brother Kyle all made the trip to SuperTarget field.

Kim said they tried to be fair in their support, but it appeared there was an OU bias. Dick and the grandparents were decked out in maroon, and Kyle and Kathy wore crimson and blue.

“I guess they tried for half and half,” Kim said.

Besides the partial parents, it wasn’t difficult to tell the sisters apart. Kim is 5-6 with brown hair, while Kirstin is a 5-9 blond.

“I’m the taller Karfonta,” Kirstin said.

Kim said the sisters didn’t bet on the contest, but one might wonder.

And Kirstin refrained from singing the “Boomer Sooner” ballad to Kim.

“I’m usually the one talking trash, but today I just told her, ‘Good game,'” Kim said.