Kirsten Flipkens played her first professional match in 2001. For more than 21 years, the Belgian has seen, played and sometimes beaten greats from multiple eras of tennis.

But at the age of 36, she's finally decided to hang up her racquets. At the start of June, Flipkens announced Wimbledon -- where she achieved her greatest Grand Slam success, reaching the semifinals in 2013 -- would be her final singles tournament.

Ahead of the tournament, Flipkens sat down with WTA Insider to explain what led to her decision, to reminisce over her career highlights and to look ahead to what's next.

WTA Insider: You've had a great grass season for a player about to retire: quarterfinals in 's-Hertogenbosch, then upsetting Elise Mertens in Eastbourne. Did they make you change your mind?

Flipkens: The thing is, the rest of the season you've got clay courts, you've got hard courts. Grass is just my favourite surface. That's also why I wanted to stop at Wimbledon. It's just tough to go every day for practice again. Physically, mentally, I feel it's the time to say goodbye even though I had amazing results in the last weeks. There's a time of going and the time is right.

WTA Insider: Was it a case of waking up one day and realising you didn't want to push yourself any more, or have you come to the decision over a longer period of time?

Flipkens: It's been a process. I've been pushing myself a lot throughout my career with injuries and comebacks. Actually, three years ago it was my plan to maybe retire in 2020 at Wimbledon, but then we all know what happened with the pandemic. So I said, let's give it one more push and have a good pre-season for 2021. Then I had my injury with the ankle in January. But I'm pretty stubborn, and the thing is that for me, it always had to be Wimbledon where my last match would be. So this year, third time lucky!

Kirsten Flipkens celebrates after defeating Petra Kvitova in the 2013 Wimbledon quarterfinals.

Ben Stansall/Getty Images

WTA Insider: You announced your retirement from singles. Does that mean you'll be carrying on in doubles?

Flipkens: I just announced the singles because I wasn't sure about doubles. Grass is an exception, but normally when I'm at home I'm always watching the clock every 10 minutes when I go for a singles practice. But honestly, I still love playing doubles. I like to play the game, to play the volleys, to do some trick shots here and there. It's a totally different game.

I also still enjoy the travelling -- just not as much as we do for singles. You have to travel for 30 weeks a year for singles. But in doubles, you only have 10 or 11 tournaments that count for your ranking, so you can be much more picky about which ones you play. I think for now, the plan is still to continue in doubles, but I don't know for how long. I made a schedule from now until the US Open, and then I will see from there how I feel.

WTA Insider: Looking back to your semifinal run here in 2013, can you talk about how you felt before and during that tournament?

Flipkens: I remember that year I had just played the finals in 's-Hertogenbosch, I lost to Simona Halep, and that was really special because it was like a home tournament for me. Going into Wimbledon I was totally confident. At the beginning of the run, the first and the second round, I was a little tight and tired. But after that I started to feel better. I started to feel like, 'Hey, I could go for a big run here.' That's what happened in the end and I have unbelievably great memories from it.

I didn't look forward in the draw any more than round by round, but when I won my third round I knew it would be a big challenge to play Flavia [Pennetta]. I remember us playing here on Court 18, and it was a really intense match from both sides. We were both playing with quite a lot of nerves, I would say -- that was normal. You feel like you can go into the quarterfinals of a Slam and I'd never done that before. And then playing [Petra] Kvitova, a two-time champion, on Centre Court and winning 6-4 in the third -- it was the cherry on the cake.

WTA Insider: Winning Québec City in 2012 was another career highlight for you. What were the circumstances around that tournament?

Flipkens: I was not even planning on going there. Kim [Clijsters'] retirement was at the US Open in 2012, and Québec was the week after. I was still far out from the main draw and decided if I was only in qualifying, I wasn't going to go. Then I stopped looking at the list.

The only thing I did in New York after Kim's retirement was enjoying it with her, having nice dinners, going partying a little bit and totally not practising at all. My plan was to have a week off. Then someone from the WTA office came up to me to tell me I'd moved into the main draw, so that was a hell of a story. Going to Québec not having practised as I should have, and drawing the No.1 seed Cibulkova in the first round. Then whatever came after was a bonus, and look what happened.

WTA Insider: Was that a lesson in how fewer expectations enabled you to play at a higher level?

Flipkens: Exactly, totally. The less expectations the better. The more relaxed you feel, the better you play. That was a nice example.

That's also what I told myself the last couple of weeks -- just enjoy being on court, just enjoy being on your surface, just let it sink in. It's easier said than done to tell your mind to relax and to have fun, though. But that's what I'll try to do here. The reason I started playing the game is because I love it -- I love to play drop shots, I like coming to the net, I like playing tweeners. I'll try to show a little more of that the next few days.

WTA Insider: Over your career, you've become known for your hot shots. Are there any that you particularly recall?

Flipkens: If I had to pick one shot that stands out, it would be the one against Kristyna Pliskova in Seoul [2016]. The one-handed behind-the-back backhand winner. And the one against Eugenie Bouchard in Indian Wells [2019], the tweener at the net. Yes, I can say I hit a couple that were really nice.

I thought I should have won Shot of the Year a couple of times, but Aga [Radwanska] always ran away with it. But at least I was on the other side that time she hit the behind-the-back volley winner in Miami!

WTA Insider: How did you evolve your game over the years to adjust to different eras of the sport?

Flipkens: Honestly, if I look through my career I didn't make that many adjustments. Of course, you always work on some things, but for example, I never changed my technique, not once. Not with the forehand, backhand, serve, nothing. I think a lot of players do that, but I've always been a player who goes by her gut feeling.

Of course, you had Kirsten Flipkens who was 20 years old and you have Kirsten Flipkens who is now 36 years old, and with the experience you get the more you realise what you should do - like on surface, to come more forward over the years because my net game is pretty good. You just have to improve what is already good, and make better what is not as good.

WTA Insider: Are your various comebacks, especially from life-threatening blood clots in 2012, among the things you're most proud of?

Flipkens: Definitely. There have been a lot of times in my younger career, when I was 22 or 23, when I had a lot of injuries. Basically every year I was out for three or four months. My wrist, my back, blood clots. I always doubted, should I come back one more time or not? I had a lot of tears also, because I felt that my body was not letting me do what I wanted to do or what I was capable of. 

But I knew that when my body was healthy I was for sure a Top 100 player. Keeping that in mind, knowing I could still go for a big run somewhere at a Slam -- which happened in the end, luckily -- that's something that kept me pushing.

A lot of people in Belgium promised me a nice career, a big career, Top 20 after I was No.1 in juniors. I was 26 when I broke through there. That's pretty late for a female player. I always had to keep pushing myself to do it. I'm just happy that all the work I put in and every comeback I made paid off.

WTA Insider: Those "late" breakthroughs are becoming more commonplace now. Jabeur, for example, is playing her best tennis at the age of 27.

Flipkens: I think players like Ons and myself, we are like a puzzle and you have a lot of pieces in it. One shot, you can go for your backhand, but you can also go for your slice, you can go for your drop shot. To make the right decisions at the right time, I think it just needs more experience and more years to totally fulfil your potential. 

Kirsten Flipkens celebrates after defeating Venus Williams in the first round of the 2016 Rio Olympic Games.

Luis Acosta/Getty Images

WTA Insider: What would be your top three matches of your career?

Flipkens: No.3 would be my last Billie Jean King Cup win at home against Kazakhstan, in 2020 [Flipkens clinched the tie by defeating Zarina Diyas 6-3, 6-4]. No.2 would be my win against Venus Williams 4-6, 6-3, 7-6(5) at the Rio Olympics. And No.1 is, of course, against Petra here at Wimbledon.

WTA Insider: What was the one that got away?

Flipkens: I never passed the second round of the French Open, but I think I had a good opportunity to make the third round in 2014. I was No.21 seed and I lost to Julia Glushko 6-4, 3-6, 6-4. That's one I still think about. I still think I should have won it.

WTA Insider: What was the loss you learned the most from?

Flipkens: My first match in the Billie Jean King Cup, losing to Meghann Shaughnessy 6-7(4), 7-6(8), 9-7. I was a kid of 17 years old playing a Top 20 opponent for the first time and I had match points. That loss, that hurt a lot, one of the most painful losses in my career. But I also learned that I was able to go to the limit with a top player.

WTA Insider: What comes next for Kirsten Flipkens?

Flipkens: I have no plans. I've had a few players ask me here and there if I would be interested to stay on the tour to coach them. I definitely think I will, but I will first focus on myself with doubles and then see from there. I still want to travel 15 weeks per year, just not more.

But the first thing I will do after Wimbledon is go to Ibiza [island on the Mediterranean Sea] and enjoy life a little. 

WTA Insider: How would you like to be remembered?

Flipkens: As a slice-and-dicer! As a player, I think a lot of people will remember me as an annoying one. I know a lot of players told me, now you're quitting, finally we don't have to go under that slice any more.

But as a person, I hope I will be remembered as a very easy-going one who always looks on the bright side. I've always been someone who knows that there is a life beside tennis and that I like to enjoy life also. I've always been relaxed; I would never not say hi to an opponent. 

Eastbourne: Flipkens upsets Mertens for 1st Top 30 win since 2019