Swiss seventh seed Belinda Bencic became the highest-ranked casualty at Wimbledon when she retired from her second round match against American qualifier Julia Boserup on Thursday. Bencic was 6-4, 1-0 down on Court Three to the world number 225 who is making her Grand Slam debut. Bencic had only completed her first round match late Wednesday and struggled Thursday with what appeared to be a wrist injury. Boserup, 24, goes on to face either Andrea Petkovic of Germany or Russia's Elena Vesnina for a place in the last 16.