Weary from three straight weeks of tennis and unwilling to make a trans-Atlantic flight, U.S. Open champion Serena Williams withdrew from the Seat Open on Tuesday.
This is the fourth tournament from which she has withdrawn this year. The WTA Tour said she could lose $16,900 in year-end bonus money for the no-shows.
Williams was the top seed for this $180,000 tournament in Luxembourg and was to begin play Thursday after receiving a first-round bye.
"I feel I cannot make the journey this week, as I am mentally and physically exhausted after three consecutive weeks of tennis," she said.
The organizers of the Seat Open called Williams' decision "incomprehensible" and said it showed "lack of respect" for tennis fans.
Players lose one-thirteenth of their bonus money each time they pull out of a tournament to which they have committed.