The tennis courts might be closed, but Zoran Kerezovic’s game has never been stronger. The 66-year-old retiree has been rallying regularly with his two grandchildren in the backyard.
Mr. Kerezovic and his wife live with their daughter, Nada Kerezovic, and her family in Campbell Hall, a hamlet about 70 miles north of New York City. Born in Serbia, he moved to New York when he was 19. He didn’t start playing tennis until his mid-40s, but now considers himself a die-hard fan—Serbian starNovak Djokovic is his favorite player….