Raducanu among the fallers in round one
While Iga Swiatek eased into round two for the loss of just three games, Wimbledon winner Elena Rybakina was defeated in straight sets by Clara Burel.
Sofia Kenin's lack of game time was illustrated in her loss to Jule Niemeier, while this was also a factor for Naomi Osaka as she was ousted by Danielle Collins.
However, one of the main talking points on day two was the loss of the defending champion, Emma Raducanu, with the Brit falling in straight sets to Alize Cornet.
It wasn't a stunning loss in terms of match pricing, but it does raise the question as to where will Raducanu end up this season and beyond? Her serve continues to fail to inspire confidence.
Keys' serve makes her favourite over Giorgi
One player hoping to make a big impact towards the end of the season is Madison Keys, who is up against inconsistent Camila Giorgi this evening.
Keys' talents have been renowned on tour for many years, but injuries have unfortunately had a tough impact on her opportunities in majors.
Now ranked 20, Keys is definitely one of the players who will have realistic expectations to get to the business end of the event and the justified 1.501/2 about her - given her edge on serve - looks about right.
Haddad Maia favourite over Andreescu
For me, though, the match of the day is Beatriz Haddad Maia versus 2019 champion Bianca Andreescu.
It's actually Haddad Maia who is the slight 1.9210/11 favourite after a stunning year so far, and then reaching the final in Toronto several weeks ago - she also performed an infamous double-bagel against Ana Konjuh on Monday here as well, so is clearly playing at a high level.
This is a higher level than Andreescu has managed of late, with four defeats as pre-match favourite in her last four events, so my lean is for Haddad Maia to take the match of the day.
Samsonova taking unbeaten run into Fernandez match
We also have last year's beaten finalist, Leylah Fernandez up against Ludmilla Samsonova, and she's the pre-match underdog at 2.727/4.
Samsonova's numbers this year have been superb on hard court (108% combined service/return points won) with big edges over Fernandez both on serve and return.
Factoring in also that Fernandez hasn't impressed after taking three months off following the French Open, with just two wins over mediocre opposition, and Samsonova coming here off the back of two hard court titles, I like the 1.574/7 about Samsonova to progress here.
Serena underdog to continue tournament
Finally, Serena Williams is the underdog at 3.2011/5 against Anett Kontaveit, which is difficult to dispute.
The American legend faces a big increase in opposition quality against Kontaveit here compared to Danka Kovinic on Monday, and there's a real threat that this will be the last time we see Serena in competitive action should she lose against the Estonian here.