Federer, Nadal and Djokovic dominated tennis for years. But there were also so many lessons about leadership and growth.

“Roger Federer won 80 percent of the matches he played, but he only won 54 percent of the points he played,” Barnes said. “He knew how to put a point behind you and get the next one, the biggest ones.

Just as he did standing across the net for so many years of his tennis career, Roger Federer saw it coming. Last week, at the headquarters of Swiss Tennis in Biel, Switzerland, with about 50 junior ...