Williams returned from giving birth to her first child to reach the 2018 Wimbledon and US Open finals, but suffered upset losses in both to leave her stuck on 23 major wins.
Other tennis stars like Serena Williams and Kim Clijsters played tennis after becoming a parent.
Naomi Osaka's 6-2, 6-4 win over Serena Williams quickly became infamous for the American's flare-up in the second set.
Sloane Stephens said on-court coaching created a connection between players and fans.
At the moment, on-court coaching is only allowed in WTA events but not on the men's ATP Tour or at the four Grand Slams.
20-year-old Naomi Osaka won the 2018 US Open title by defeating Serena Williams.
Naomi Osaka made headlines last month when she stunned Serena Williams in New York to win her maiden Grand Slam.
Japanese tennis player Naomi Osaka has admitted that the memory of 2018 US Open final is a little bit bittersweet for her and definitely not a happy one.
It comes less than three weeks after the tempestuous US Open final.
Serena Williams said she had not seen her coach make a gesture and labelled his subsequent admission "a really confusing moment".
Men were fined 344 times compared to 140 for "audible obscenity" and 287 to 67 for unsportsmanlike conduct.
Serena Williams said she was punished for saying something where men have said far worse without incurring such a penalty.
Carlos Ramos has been praised for acting with "professionalism and integrity" by the International Tennis Federation after the umpire was labelled a liar and a thief by Serena Williams.
The first Japanese player, man or woman, to capture a Grand Slam singles title, Naomi Osaka won her first WTA tournament at Indian Wells in March.
Serena Williams claimed that chair umpire Carlos Ramos meted out penalties for infractions that male players could have gotten away with.
Serena was fined for coaching, racquet abuse and for verbal abuse when she accused umpire Carlos Ramos of being "a thief" during Saturday's stormy final.
Serena Williams could face further sanctions for her actions in US Open final, the WTA issuing a statement that they will be looking into the incident.
Serena Williams tearfully accused the chair umpire of being a "thief" and angrily demanded an apology from the official.