Serena Williams screams to Line judge “I would kill you” and later on goes away [HQ] US OPEN Kim Clijsters Semi-Finals Women
http://www.youtube.com/watch?v=13xx50-ES2A
When I watch that clip in full-screen mode (during the replay in slow motion), it looks to me that her left food was on the line. But it also seems that the call came a second or two beyond the point in which you would have expected a foot fault call. Hard to say for sure.