Carlos Ramos returned to the umpire's chair for the first time since being called a "thief" by Serena Williams, overseeing a Davis Cup match on Friday.
He was in charge as Marin Cilic became Croatia's most successful Davis Cup player, giving his country a 2-0 lead over the USA in the World Group semis.
Happily for Portugal's Ramos, there were no controversies as Cilic beat Frances Tiafoe 6-1 6-3 7-6 (7-5).
Borna Coric won the opening singles 6-4 7-6 (7-4) 6-3 against Steven Johnson.
It means Croatia are firmly in charge of the best-of-five-match tie in Zadar going into Saturday's doubles and Sunday's reverse singles matches.