Naomi Osaka's Eiffel Tower-inspired outfit choice has been labelled 'problematic' by her beaten opponent following their French Open first-round encounter on Tuesday.

Osaka defeated Germany's Laura Siegemund 6-3, 7-6 on Court Suzanne Lenglen to set up a second-round showdown with Croatia's Donna Vekic on Thursday.

However, Osaka's array of shots were not the main talking point - with Siegemund bemoaning the preferential treatment afforded to the sport's 'bigger stars' and how the rules are are not always applied to them.

The No 16 seed Osaka wore a custom-made Nike outfit design that has been likened to the Eiffel Tower.

The sequined and glittery gold ensemble also included a ceremonial black skirt and sleeveless beaded bodice which she wore walking out on to the court before taking off the latter two items.

And while the beaten Siegemund had no issue with the actual outfit design or the result, she expressed some frustration at the time Osaka was awarded to take off her outer garments in comparison to how long players are allowed to do meaningful things during matches.

'I couldn't care less,' she told TNT Sports.

'I come here to play tennis, not to put on a fashion show. And if others want to put on a fashion show, then they should go ahead and do it. That's totally fine with me.

'I find something else problematic. In our sport, at every tournament they count every second, right up until you've unpacked your water bottle. But she can have a minute-and-a-half to change. I have a problem with that, because these rules simply exist and they are what they are - every second is now being watched so closely for us.

'And I also think that with performances like these, every second should be accounted for. That's the only thing regarding the rules that I don't think is OK and where, once again, bigger names are treated differently.'

Speaking about her outfit, Osaka said post-match: 'It's very couture. You know the Eiffel Tower at night when it's sparkly. I kind of think I look like that a little bit.

'I don't really feel like it's too much of a big deal to do that and then play after [in terms of making a fashion statement and then playing tennis]. I could see where people would think I feel a little stressed or whatever. I think that's kind of the thing about it.

'Like sometimes people say athletes are, like, in show business or entertainers or whatever. I feel like for me, grand slam walk-ons are the only time that I possibly feel like I'm an entertainer.'

The 28-year-old and four-time Grand Slam winner - who wore a jellyfish-inspired dress at the Australian Open in January - added that her only concern was that the glittering dress might be too reflective in the sun.

'When I first saw it, I felt like I look like the Eiffel Tower at nighttime when it's bright,' she continued.

'Then I actually got a little worried because when the sun hits the dress, it reflects a lot, so I was a little scared the umpire was going to kick me off the court.

'I got two back-up, normal dresses - thankfully I didn't have to wear them.'