Ostapenko is a strange case. Her very 1st WTA title (2017) was a slam event. But she has only added 1 minor title for a grand total of 2. Osaka has fared better but is still rather odd. A total of 3 titles -- all but 1 of them is a slam title. Will Jelena and Naomi be the WTA versions of Stan Wawrinka?
I don't see them being the WTA version of Wawrinka and I'm not sure I can find one - DelPotro maybe..... but he was plagued with serious injuries after winning the USO so it's not really the newly found glory that dragged him down.
I think Kerber is more like the WTA corresponded of Wawrinka.
- Both had an average career until their late 20s - solid top 10/20 players but only winning a hand full of small tournaments and few occasional QF/SF runs at GSs during the previous 4-5 seasons leading to their respective breakthrough seasons
- Both won their first GS at 28/29 years old and climbed to the top of the rankings those years - Kerber #1 (2016), Wawrinka #3 (2014)
- Both won their subsequent GSs within the next 2-3 seasons but no other material wins in big tournaments in between - Wawrinka won one Master1000 in 2014 though, but Kerber doesn't have any Premier5/Mandatory title (each played and lost 2-3 finals)
- Both lost another GS Final after winning the first one
- Both started to faded away the next season after their 3rd GS win