Editor’s Note: Following an illustrious career in international water polo, Ratko Rudic—the only man in history to coach four Olympic gold water polo medalists—has officially retired from the sport.

In the pool of the Mompiano sports center in Brescia, Pro Recco celebrates. The team led by Sandro Sukno wins the 37th championship in its history, the fourth consecutive with this coach on the bench.

This represents an important opportunity for a player who may prove pivotal to American hopes in the upcoming Tokyo Olympics. A star performer for four years under Cal Head Coach Kirk Everist, in 2017 ...