Joachim Johansson is threatening to drive a wedge through the Hewitt family after he beat Andy Roddick to reach the semi-finals of the US Open on Thursday.
The Swede will play Lleyton Hewitt in the last four in a match that will test the loyalties of the Australian's sister Jaslyn, Johansson's girlfriend.
"You can't pick your brother but you can pick your boyfriend, so I hope she'll support me," Johansson said.
"Lleyton and I are good friends. I hope we'll be good friends after Saturday."
The 22-year-old Johansson, the 28th seed, will be playing in his first Grand Slam semi-final.
He added: "I was supposed to be playing golf with my dad in Scotland
this weekend but I'll have to change my plans now.
"It's going to be a very tough match. It will be a little
bit weird but we know each other's games well. I'm going to have
to serve well and move well."
Hewitt, the 2001 champion, trounced Germany's Tommy Haas 6-2
6-2 6-2 in his quarter-final.