But a crucial double fault opened the door for Errani , who rallied and won on a tiebreaker .
After the bagel exchange , Williams had a chance to serve out the match at 5 - 3 in the third .
A crucial double fault opened the door for Errani , who rallied and won on a tiebreaker .
After the bagel exchange , Williams had a chance to serve out the match at 5 - 3 in the third .