Interesting dynamic in the late 80's (1988-1989). While old Evert was beating a young Fernandez , young Fernandez was beating a physically mature Sabatini , and physically mature Sabatini was beating old Evert! From March of 1988- Oct of 1989, Evert was routining Fernandez in 3 matches ( 6-0 in sets) Sabatini was 1 and 4, in the first five times Fernandez and she met ( of the 11 sets they played, Fernandez won 8) while Sabatini was winning 2 of 3 matches against Evert (and 5 of the 8 sets they played). It was not until in the early 90's that Sabatini began to get a series of victories over a more mature Fernandez.
Here's the explanation for why Sabatini getting a lot less trouble from Evert than this young less experienced clone of Chris' was delivering to Gabby in those years and Gabby had less trouble later on with Fernandez, when logic dictates that Fernandez should be improving with more muscle tone, experience and maturity, 3 INCHES.
That was the difference between Evert's height at 5'6 and Fernandez at 5'9. That heavy topspin was causing Evert a lot more headaches driving her further back and opening angles, than it was Fernandez because their comfort strike zone was very different! When Sabatini began to drop all that heavy high bouncing kick for a flatter game under different coaching, Fernandez height advantage and strike zone was lost in these rallies.
What was an Achilles heel for older Evert, once Sabatini grew into her adult height, strength, and most importantly stamina, was never an Achilles heel for this young immature girl in the first place! Sabatini was having trouble ever taking Fernandez into a third set, while Evert only lost one set to Mary Jo in their entire match rivalry because that extra height just meant a lack of mobility around that baseline that Chris Evert exploited virtually every time she met someone tall! Mary Jo did not have any of the early success of an Austin or Jaeger, or Sanchez, or even Maleeva against Evert, in part because of those same inches!
How tall was Sabatini? Why she was 5'9 as well at her full ht, so why wasn't Chris able to do the same thing to her, as she did to Mary Jo? She was having to stand too far back to exploit it once Sabatini grew physically strong enough to hit that topspin with even more power and racket acceleration than she could at sweet sixteen.
3 inches means a hell of a lot in matchups, as does the nature of one's basic groundstroke