Mandy Minella of Luxembourg played at Wimbledon while four and a half months pregnant.
Top seeds Sania Mirza and Martina Hingis went through several anxious moments before getting past Russian girls Daria Kasatkina and Alexandra Panova in their opening doubles match at the French Open on Wednesday. The reigning Wimbledon, US Open and Australian Open champions prevailed 7-6(4), 6-2.
The games were scheduled to start at 1000 am local time (2300 GMT) but did not get underway until about 1130 after Victoria state's environment watchdog said air quality had plunged to "hazardous" levels overnight.
No current athlete in the world of sport can match the 31-year-old for reliability at present and the American, despite a brief blip, eased past Luxembourg's Mandy Minella 6-1, 6-3.
World number two Rafael Nadal dropped a set at the Barcelona Open for the first time in four years before advancing to the last 16, beating Argentine Leonardo Mayer 6-7(7), 6-4, 6-2 on Wednesday.
Serena Williams launched a charm offensive on Sunday as she sought to broker a truce with Maria Sharapova and calm the storm surrounding comments she made about a rape victim.