What did Serena Williams bring to tennis on the court and off the court?
The impact was huge. It touches me a lot because my career has been with Serena and personally, she has been an inspiration. She pushed me to be a better player all the time, as she pushed a lot of players.

She brought the game also with Venus at the same time physically in another dimension. But also not only physically but mentally in the way every time coming on the court - just the idea I want to win and I want to be the best player on the court. 

That really pushed I think also the game and we had also other players like this in history of the game and great professionals but mentally it became another dimension with Serena. 

I have to be honest, she's the best I had to play in this game in terms of mental conviction - I think she was helped in a lot of things, but she always made the effort to come through and to overpass a lot of things. She had a lot of things to prove probably to herself, to a lot of people and she did it in amazing ways. So personally I am really grateful. I would never have had that career without Serena that's for sure. So now it's the end and it's time to be the end. But the impact she will [leave] in the history of the game is huge.

Do you see the potential in somebody to become the next Serena, for example, to dominate the game or like her in the future?
To dominate as she did, win as much as she did, we cannot say that. Generations are also changing. The world is changing a lot. The history of the game will be written in a certain way, maybe a different way. Maybe on the men’s tour or women’s tour someone will win again, 20 grand slams. We like that kind of story, of course, because we like to think it was impossible, but that player shows us it's possible to go further and to push the limits again. And we like it.

Is it going to be possible? Do I see it now? I don't see it now. But everyone was talking about Coco Gauff, even two years ago today, because we expect too much too early from the players. 

We have to pay attention of course on that. Also, it's great to dream big, of course, and I've been dreaming big. I push the young kids to dream big. But also to stay in the reality of it is very important. The reality is hard work [like with] Serena, as many as all these champions that we are talking about, have been working so hard. 

So I think that today in this world where we want to get everything and very soon. I think that’s probably the biggest limit today to this kind of challenge in the future. Because the investment is this time, this passion and not everything comes like this very easy. Sometimes we can think that in our society, but it's not the case in life and especially when you are when you are top athletes.

How would you describe Emma Raducanu’s year since last year's US Open and what do you expect from her at this year's US Open?
I think it's time for her that the US Open is behind her. If we come back a year ago, we couldn't expect that from her. She was playing the first tournaments on the tour and then she wins a Grand Slam the way she did. We all loved it – it was with Leila. It was fresh. They were playing great tennis. 

We need personalities also on the tour and I think these two really gave us a lot of emotions last year. I was really excited about what was happening and then what happened after - we could expect this in a certain way. 

I don't know her personally. So the fact she changed coach, she changed a lot of things - everyone started to criticise this but I'm not into it really to judge this. 

The only thing I say is she needs to be focused on the game if she wants to keep a certain kind of balance in what's happening for her and after winning Grand Slam of course so much attention, so many solicitations and an agent's and probably money and a lot of things.

We can suppose that it's not easy to deal with at such a young age with no experience. But you can build, build, build because you are very good, very young and then you start winning Grand Slam early.

What happened in the last few months with her was quite normal. I think she will be relieved also. Once this US Open will be behind her. How she's going to deal with it, we will see. We can suppose it's not going to be that easy. But I think this game is full of surprises.

How many players in women's field are able to win the US Open this year? Is it a good thing or a bad thing that this number is so big in women's tennis?
The number depends on my mood but I can say 128 - probably not! But it's open, it's really open when you look at the results of even the top 10 but especially the top five in the last few weeks.

Maybe I put Iga Swiatek a little bit on the side because how many wins she had until Roland-Garros it was huge. It was also a lot but still. Of course it's only preparation for Grand Slam. 

You cannot only judge on the tournaments before the US Open but I think more like this if we talk about big champions – they didn't have the best preparation but they can raise the level during the Grand Slam if we talk about Novak Djokovic, about Rafa Nadal. We all know that they cannot be at their best level before and still raise the level during Grand Slam.

On the woman's side - and we cannot say that about all the men - I'm talking about two special guys also. So let's try to remain positive on that. 

Is it good, is it bad? I think everyone knows my opinion on that I would prefer really a few girls dominating. The two being consistent and then get the outsiders but still get the feeling that in the quarters you are almost sure to find five or six players from the top and today we cannot bet on that anymore. Everything is changing so fast and the girls they see opportunities which is good for many girls but for the popularity of the game I keep thinking that we need girls that win more consistently, more often. Because you can look at the results of certain girls for a few weeks already and of course sometimes you can have a down and it happens to everyone in your in your career. 

But it looks like it doesn't matter anymore because they will have other opportunities later. It's a feeling and maybe it's not right and we'll be glad to speak about that with players, with coaches also. I am into it but with some distance also so I don't want to be too hard in the way I talk about it but I miss that a little bit for the game and because so many people see me sometimes in the street and tell me now we don't know anymore. 

We don't know the girls names even that who won the French Open last year, who won that tournament. I want for the game I love so much - I want to make sure that it keeps the popularity that's for sure. In terms of level, we still can see a very good level of tennis for sure.

Justine Henin will be working as an expert for Warner Bros. Discovery's coverage of the US Open, which starts on Monday 29 August. Watch the US Open LIVE across Europe (ex UK&Ire) on discovery+, Eurosport and Eurosport App.