With Day One of the 2023 US Open in the books and Day Two starting with Carlos Alcaraz, Aryna Sabalenka and Jessica Pegula among those starting their campaign. We look back at five things we learned from Day One of Flushing Meadows.

From one of his best displays at Wimbledon, similar to Elena Rybakina with her illness, it has all come crashing down since then.

Holger Rune lost out to Roberto Carballes Baena in four sets on Monday. After complaining about not being on a show court, he seemingly didn't have a reasoning to make such a complaint with his poor form continuing.

He has now lost in the first round at every single tournament since and his record is even worse when you consider Hopman Cup losses. Injuries plaguing him and likely some time off to get himself right beckons. Certainly though there is some cause for concern for Rune though after another early defeat.

Another player who also looks deflated was Greek ace, Maria Sakkari. A previous semi-finalist in the year that Emma Raducanu won the title, she likely had one of her best opportunities back then at Flushing Meadows.

Two years on and she is thinking about her short term tennis future. A player who will drop like a stone in terms of her ranking after the US Open, she is considering going down the route of Muguruza and more long term Anisimova in taking a break from the sport.

But whether the calendar will allow that is another matter, with Sakkari signed up at least for now to play Guadalajara. Losing to Rebeka Masarova, she was emotional and slumped in post match press and has a lot of soul searching to do.

A player who shows real grit and fight on the court, but isn't getting the reward for the effort she is putting in. Could her time with long-time coach Tom Hill be coming to an end as Sakkari searches for answers? For now she will be searching for a plane back to Greece after another early exit.

Amid the back drop of the opening day was Billie Jean King and Michelle Obama as the US Open marked 50 years of equal prize money.

But for some, it felt like a missed opportunity. Novak Djokovic himself said post match that he wishes he would've gone on earlier albeit understanding the circumstances.

In a way, it was a rushed afterthought. A metaphor for how the women's game has been treated by tournaments recently perhaps. But a moment that could've instead seen a player such as Gauff or Swiatek headline following it in a display of the top women's players of the current generation.

Albeit Djokovic instead followed still ruling the roost and being the main attraction instead of a poignant moment for women's sport.

Speaking of Gauff, she had an outburst at the umpire Marijana Veljovic after Laura Siegemund tried every trick in the book to try and disrupt her rhythm.

As Gauff pointed out, it was more on her serve that it was the problem rather than the German's service game in which she had every right to try to slow it down.

Siegemund felt hard done by in post match press breaking down in tears, some people called it brilliant due to being fans of the drama and aggro.

Others including Pam Shriver on the ESPN coverage let out an audible sigh as another service motion featured clock management to the full. It prolonged the tie for the German but didn't do anything in terms of helping her win.

Another player who had an outburst, but a more controversial one was Alexander Bublik who said he was sick of giving 'disabled people' wins.

"I’m f**king sick of giving careers back to handicapped people," he was translated as saying.

For context, he lost to Dominic Thiem who sealed his first win at the US Open since the 2020 title. Bublik has also lost as of late to Gael Monfils and Stan Wawrinka among others. Both have come back from injury laden campaigns as of late.

As ever Bublik was in the headlines this time for the wrong reasons. He left the US promptly with him pulling out of the doubles and under a cloud of controversy. While Thiem moves on to a popcorn clash with Ben Shelton, showcourt incoming?