That is a fallacy known as argument from authority. The opinion of experts is not an indicative of truth.
To suggest that something is true only because experts say so is a logical fallacy (wrong argument) known as argument from authority:
en.wikipedia.org
Experts can be wrong live everyone else. Time can prove the opinion held by experts to be false. In the 1960s, scientists (the experts) believed that chimps are herbivores, but new observations proved them wrong, hence experts can be wrong like everybody else. In late 2019, many ESPN basketball analysts (the experts) suggested that Carmelo Anthony was done and had no place in the NBA and a few months later Anthony proved them wrong coming back to the NBA and scoring 16 points per game with the Blazers.
To consider Rosewall worse than Gonzales, it must be proved comparing their careers, not merely citing what experts say.