Ashleigh Barty produced the WTA’s best winning percentage in 2021 with a record of 42-8 (.840).

There was a big drop-off in the next four players ranked after her: Aryna Sabalenka 45-18 (.714), Garbiñe Muguruza 42-17 (.712), Karolina Pliskova 37-19 (.661) and Barbora Krejcikova 45-19 (.703). While that’s partly a tribute to the depth in today’s game, it also puts into perspective some of the most dominant seasons in history.

In a span of five years, 1982-86, Martina Navratilova produced four of history’s best six seasons in terms of won-loss percentage. The other two belonged to Stefanie Graf. Feast your eyes:

1983: 86-1 (.989)

1984: 78-2 (.975)

1982: 90-3 (.968)

1986: 89-3 (.967)

And yet, at the end of every season – even those that were tantalizingly close to perfection – Navratilova would spend considerable time tweaking her already formidable game.

“What are my strengths and weaknesses?” she said recently from her new home in Miami Beach. “How do I make it better? I was always tinkering.

“Trying to find an extra two miles an hour on the serve with the same effort, but improve the motion? A little more spin on the ball – where do you find it? In the shoulder, the elbow or maybe the wrist? Or different strings. I tinkered with my racquet – I don’t think today’s players do that enough. What feels right? The racquet should be adapted to you, not the other way around.”

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“Nowadays,” Navratilova said, “there’s no excuse not to tinker. The analytics, the statistics that are available to the players are phenomenal. You can plug up the holes much, much quicker.

“You know you have a problem at 30-all on your serve. At 30-all on their serve, this is what you do on the return. I would be looking at my weaknesses and, obviously, how I can exploit my opponent’s weaknesses. “

Courtesy of Navratilova, here’s a free clinic for the Top 10 players from the 18-time Grand Slam singles champion:

No.1 Ashleigh Barty

 WTA Player of the Year … Finished as year-end No.1 for the third consecutive year … Won a tour-high five titles, including Wimbledon, Miami and Cincinnati.

Navratilova’s take: Improve her drive backhand. Also develop a slice where she can knife it, making it more effective down the line. Right now, it’s kind of an around-the-corner slice, bending from the outside in, when she hits it. Keep that one, but also develop the direct slice, chop at the ball, hit it harder.

No.2 Aryna Sabalenka

Reached the first two major semifinals of her career, at Wimbledon and the US Open.

Navratilova’s take: I would work on her movement forward. With her power, she’s so good at getting those short balls, but she’s still uncomfortable hitting those short balls. She needs a bigger court, because she doesn’t have enough margin. So work on those balls that are inside the baseline. Most of all, control the temper better. You cannot let your head get in the way.

No.3 Garbiñe Muguruza

Won the WTA Finals in Guadalajara and finished the year at No.3 – her best ranking in four years.

Navratilova’s take: She can get a little more creative, especially with the drop shots. Her backhand slice is pretty nonexistent – you add that to your game, it doesn’t have to be great, but it drives people crazy. Maybe a little bigger kick on her serve, like Badosa and Sakkari.

No.4 Karolina Pliskova

Out for the Australian Open with a hand injury … Reached the Wimbledon final – her second runner-up at a major … Was the only player to beat Muguruza in Guadalajara.

Navratilova’s take: Similar to Sabalenka. Needs to improve her movement and moving up to take the short balls. Not enough margin for error. Those should be gimmes, like a three-foot putt and sometimes you’re watching her, holding your breath. She’s actually better at the 10-foot putts.

Draws this week: Melbourne Summer Set | Adelaide

No.5 Barbora Krejcikova

WTA’s Most Improved Player … Won singles and doubles titles at Roland Garros, as well as doubles titles with Katerina Siniakova at the Tokyo Olympics and WTA Finals.

Navratilova’s take: Get a little bit more beefy, stronger, so you can hit the ball harder with the same effort. Needs just a little more oomph. Yes, you’ll increase the errors a bit, but also – and more importantly – the rpm. She doesn’t need to hit every ball harder, but sometimes those rpms can get you out of trouble.

Photo by Jimmy48/WTA

No.6 Maria Sakkari

Reached her first two major semifinals, at Roland Garros and the US Open.

Navratilova’s take: A great athlete, she just needs to soften up a little hitting that first volley. Caress the ball a little more, so it’s easier to hit those drop shots, easier to volley, easier to take the pace off. Her transition game could use some improvement, too.

No.7 Anett Kontaveit

Finished the season in a blur, winning 26 of 29 matches and four titles in 10 weeks to qualify for Guadalajara.

Navratilova’s take: Whatever she did at the end of the year, just keep going. She’s gotten much better at the transition game – keep going. She lost the Guadalajara final because she wasn’t willing to stay in the trenches. Keep believing because, obviously, when she’s feeling it, she’s tough to beat.

No.8 Paula Badosa

Another big, late rush, including the title in Indian Wells, which helped her qualify for Guadalajara.

Navratilova’s take: So much upside. I think she can improve the variety on her serve. The slice could be better, out wide in the deuce court and up the T in the ad court. And the slice backhand – I think most of the women would make huge jumps, if they added a good slice to their game. Like so many women, she needs to work on the first volley. They’re much more comfortable hitting a swinging volley, rather than a good setup volley.

No.9 Iga Swiatek

The only player to reach the second week of all four majors … Consolidated her breakthrough at 2020 Roland Garros, finishing with a No.9 ranking.

Navratilova’s take: It’s really just a matter of believing in herself. She looked so confident when she won the [2020] French Open. You get the impression she feels like it was an accident – and it wasn’t an accident. The sliced backhand; it doesn’t bite, it just sits up there.

Photo by Jimm48/WTA

No.10 Ons Jabeur

One of the 2021 season’s great stories ... The first Tunisian to reach the Top 10 … Led the tour with 48 singles wins.

Navratilova’s take: Take care of the body – the game is all there. I would play a little bit less next year. Eighteen tournaments should be the cutoff. What happens, even if you lose early and you try to make it up the next week, you don’t ever rest and get a chance to work on your game. It’s impossible.

Other notable players

No.13 Naomi Osaka

Opened the Grand Slam season with a victory at the Australian, the fourth consecutive year she’s won a major … Played only eight matches after withdrawing from French Open before second-round match in June.

Navratilova’s take: Develop a little more safer, median game. More shape on the shots. She’s so strong, she could still have more topspin on her shots to give her the safety. Serena did that beautifully, and that’s what she can do.

No.19 Emma Raducanu

Won the 2021 US Open in stunning fashion, beating fellow teenager Leylah Fernandez in the final … Became the first qualifier to win a major.

Navratilova’s take: You need to have consistency and confidence and, with a new coach, that could take a few months. Think long term. What’s your best chance of winning? You don’t want 20 different voices telling you 20 different things. Everybody wants a piece of her; when you win, everyone’s calling. Keep it simple; so many people overcook that. Keep that team small and give it time to come together.

No.23 Belinda Bencic

Won Olympic gold in singles and silver in doubles

Navratilova’s take: It seemed like she was going to be the next star; she beat Serena, when she was No.1. She’s had a lot of injuries and been inconsistent. Which is funny, because when she was playing well, she was so consistent. Could use a little more shape on the ball and become a stronger player. It makes everything so much easier.

Photo by Jimm48/WTA

No.41 Serena Williams

Won’t be on hand in Melbourne to go for record-tying 24th Grand Slam singles title because of medical advice from her team … Played only 17 matches in 2021.

Navratilova’s take: She doesn’t need to make any tweaks, she just needs to be healthy. She needs confidence in her serve, to know that it’s going to be there. But for that you need to play matches. She’s got to start playing in the spring, maybe at on the hardcourts at Indian Wells and Miami. You have to play matches before going on the grass, which requires different muscles. No matter what training I did, I was always more sore after playing a couple days on grass than any other surface. Wimbledon and the US Open are her best chance to win another major. She’s got a shot at those two. Condition the body and minimize the possibility of injury. Bottom line: Get more matches.

No.46 Bianca Andreescu

Sitting out for the moment, pursuing mental health … 2019 US Open champion … 17-12 in 2021 with 0 titles.

Navratilova’s take: Health is everything for her. She’s been injured more than anybody, and needs to find out why. Is it training, diet – or is her body just not capable of staying healthy? Something’s off, because she’s so sturdy. She’s the only one who knows what she needs regarding mental health. It all might stem from worrying about her body.