In the men's singles, four-time champion and world No. 1 Novak Djokovic hit 13 aces and 37 winners as he eased past Denis Kudla of the USA 6-3, 6-2, 6-2. Williams will follow in that arena, facing 18-year-old Kaja Juvan of Slovenia.
Kvitova, who won titles at the All England Club in 2011 and 2014, wasn't even sure she could compete at the tournament this year until right before it began.
So, what is in him that gets the better of all the top players?
The two men pushed each other all the way in the third, but it was an aggressive Nadal who smashed a forehand victor to clinch a 7-5 tie breaker and take a two sets to one lead, and prompting the Spaniard to leap into the air and perform a fist-pump, knowing momentum had swing his way.
"I think overall today I was just really clear", Barty told press afterward.
Williams played her match with good friend Meghan, the Duchess of Sussex, watching from the stands. She made no mistakes on her second attempt, however, converting her first match point with an ace.
It was Barty's her 14th straight victory.
Kyrgios is capable of being as entertaining and befuddling a player as there is and showed why throughout this 3-hour-plus contest that overshadowed everything else going on around the grass-court Grand Slam tournament on Day 4.
Not satisfied with cheering on her female compatriots as they beat England to set up a World Cup final against the Netherlands, she has also been staying up late to watch her countrymen reach the Gold Cup final, where they face Mexico in Chicago.
"I love to play both whenever I can", said Barty, who dropped only one game partnering former world No.1 Victoria Azarenka in their doubles opener on Wednesday. "I was able to implement what I wanted right away and put the pressure straight back on her". She understands me, she understands the game because she's a player, we train together in the mornings.
Women's first round: No. 3 Karolina Pliskova beat Monica Puig 6-0, 6-4; No. 7 Simona Halep beat Mihaela Buzarnescu 6-3, 4-6, 6-2; Danielle Collins beat No. 12 Anastasija Sevastova 4-6, 6-4, 6-3; Cori Gauff beat Magdalena Rybarikova 6-3, 6-3.