LONDON -- Serena Williams walked into her news conference at Wimbledon holding her phone, a cold bottle of water and a statistics sheet that reinforced what was clear from watching her third-round singles victory Saturday:
She is as close to being back to her best as she's been in a while.
Williams, hampered for much of this season by injuries or illness, took a step forward against 18th-seeded Julia Goerges, a powerful hitter in her own right who lost to the American in last year's semifinals at the All England Club. Sure enough, Williams hit serves at up to 120 mph, put in a tournament-best 71 percent of her first serves, never faced so much as one break point and won 6-3, 6-4.
"It's been an arduous year for me," said Williams, who had competed only 12 times in 2019 until this week, mostly because of a bothersome left knee that finally is pain-free. "So every match, I'm hoping to improve tons."
About 4 1/2 hours after getting past Goerges at No. 1 Court, Williams headed out to Centre Court for her much-ballyhooed debut as Andy Murray's teammate in mixed doubles.
Other than one slip near the net when she lost her footing in the first set -- she was fine and laughed it off -- Williams looked good during the 6-4, 6-1 win against Andreas Mies and Alexa Guarachi, including smacking one serve at 122 mph, equaling the fastest hit in singles by any woman (her, naturally) during the tournament.
"Andy and I both love the competition. I know we both want to do well," Williams said. "We're not here just for show."
Two more key stats on the paper she brought to her media session: She produced more winners than unforced errors, 19-15, while Goerges finished with 32 forced errors, a reflection of just how difficult Williams can make it for opponents to handle shots she sends their way.
"I play pretty good when I'm calm, but also super-intense, just finding the balance in between there," the 37-year-old Williams said. "So it's a hard balance to find, because sometimes when I'm too calm, I don't have enough energy. Still trying to find that balance."
Goerges credited Williams with causing havoc with her returns, as well. After averaging 10 aces in the first two rounds, Goerges was limited to half that many.
"It's fair to say that she builds up enormous pressure with her returns," Goerges said. "That means I need to go to the limit in my service games."
Williams beat Goerges in the semifinals last year before losing to Angelique Kerber in the final. She will next face No. 30 Carla Suarez Navarro, who made it to the fourth round at Wimbledon for the third time by beating unseeded American Lauren Davis 6-3, 6-3.
Top-ranked Ash Barty also made it through to the second week, winning her 15th straight match. The French Open champion beat Harriet Dart 6-1, 6-1 and will next face Alison Riske of the United States.
Two-time Wimbledon champion Petra Kvitova, who a week ago wasn't even sure if she could hold a racket in her left hand, reached the fourth round at the grass-court Grand Slam for the first time since her last title at the All England Club in 2014, beating Magda Linette 6-3, 6-2 on No. 2 Court.
Kvitova, seeded sixth, broke her opponent three times while never giving Linette a chance to break back even once.
The 29-year-old left-hander from the Czech Republic was attacked in her home in 2016, needing surgery on her playing arm. She reached the Australian Open final at the beginning of this year but pulled out of the French Open with an injured left forearm.
She decided to play Wimbledon at the last minute.
"So far it's OK," Kvitova said. "I'm really glad that I can play my game without any pain."
Information from The Associated Press was used in this report.