I fully believe that prime Martina and prime Steffi would relish playing each other. That's just their nature of who they are as competitors. Martina was the ultimate matchup for Steffi as far as playing someone that gives you a target goes. Plus, no one challenged Steffi's backhand as much as lefty Martina. A match with her always let Steffi know where she stood with the quality and accuracy of her backhand. Also, Martina said in the early 90's that she enjoyed the challenge of playing Steffi more than any other rival that she had.
If they played ten times, my natural inclination to believe that a good serve and volleyer will defeat a good baseliner makes me think that Martina would win at least six of those matchups. But it would not surprise me if Steffi was the one who would win six instead.
Pure conjecture and fun to think about.
I'm surprised that Martina won 4 out of 5 at the Open. But I think their indoor matchups like 92 Zurich or 93 Tokyo might give us better clues to this hypothetical.
I would guess their head to head going something like this. 10 matches per surface:
Rebound ace: Graf wins 8 out of 10. I think this would have been Martina's worst surface by far, much worse than clay, but fortunately it did not exist until the end of her prime. A champion of Martina's stature and talents wouldnt be weak anywhere, and this was also Graf's weakest surface too, but I still think their most one sided head to head would be here. It would just be hard to employ the kind of game she would want to vs Graf on these sticky, very bouncy, and fairly slow courts.
Clay: Graf wins 7 out of 10. I think they would have had some great battles but ultimately Steffi would usually prevail. When Martina played at the top of her game (which would probably happen 60% or more of the time) the matches would look alot like the 87 French final and could go either way each time. When Martina was even slightly off Steffi would roll her. Which leaves a head to head roughly like this.
General slow to medium paced hard courts (most of the regular tour events): Martina wins 6 of 10.
Fast hard courts (U.S Open style): Martina wins 7 out of 10. I could be way off here but I am basing this on their factual U.S Open history that I spoke off at the beginning which seems to favor Martina in the head to head on that surface.
Modern fast grass: Tied 5 to 5. It is funny I am giving Graf better success rate here than the U.S Open, when Martina is generally considered the Wimbledon GOAT, and Graf has the superior U.S Open and general hard court record. However I like to look at matches that did take place, and even if Martina was arguably a bit past their prime in their Wimbledon matches, Graf fared much better in the actual history between them at Wimbledon than the U.S Open. The way Martina was taken apart in parts of the 88 and 89 Wimbledon finals, despite going 3 sets the combined games are 35-20 in Graf's favor, would suggest even prime Martina having no easy time here, however I am also sure Graf would have a very tough time with Martina's attacking style on this fast court.
Old slower grass events: Tied 5 to 5. There used to be a large grass season and a great variety of different speed grass events, including 2 or 3 majors. Martina was less formidable on slower Australian grass than Wimbledon grass for instance, although still outstanding. Given Graf's relative decline on slower Australian hard courts, I imagine the same would hold true for her. Leaving a similarily even battle.
Carpet or Indoors: Martina leads 7 to 3. Steffi was a great indoor and carpet player, and did beat an extremely good Martina in the 89 YEC, but peak Martina was almost unbeatable there.
So that leaves a final head to head of 30-30 if the matches came off the way I broke them down per surface. Since rebound ace didnt exist almost all of Martina's prime though it would come out 28-22, so more along the percentage suwanee gave in Martina's time. In todays court conditions, with no carpet events, slower grass, slower hard courts, faster clay, Steffi would win more than 50% of the time though, although neither would be as happy.
