I found that casually searching information about Vilas. I had heard that was an important match for Guillermo. The Fibak vs Vilas was a tremendous battle, according to the article. Probably Fibak was going to win the match anyway, who knows. Then it seems that Orantes was playing better than Vilas in that tournament, the spaniard had beat him that year in Tehran, that title was destinated for Orantes, he deserved it.
Interesting story I read in that website too:
When Fibak was 4-1 in the fourth set of the final, they did an interview with the actor Kirk Douglas, which praised the game of Fibak. They showed it in the big screens. He got not only distracted seeing the actor talking about his game, but also listened to the wife of Douglas supplementing her husband's words: "Despite the score, never count out Orantes; care that he never gives up ... ". After the chair umpire manifest the classic "time" for the players return to the track, spectators attended another match. The distraction of the Polish destroyed his concentration and Orantes survived as the wife of Douglas predicted. Same screens would show later "Orantes champion" and the score 5-7, 6-2, 0-6, 7-6, 6-1. When the tie-break of the fourth stage scored 7-1 for Orantes, his opponent could not erase from his mind the images that the screens headers showed him in the fateful break between the 5th and 6th game of the fourth set. Who some time after was the commissioned to playing tennis with his compatriot, Pope John Paul II, was still seeing the wife of Douglas with his foreboding message: "Beware that Orantes ...".
Orantes had not many great performances in hard surfaces, right? So I wanted to say it looks like they both would have excepcionals performances in hard or carpet-when they were inspired or if they liked that particular tournament- but not all the time.