Chair umpire Carlos Ramos has issued a code violation to Croatia after Marin Cilic slammed his racket to the clay and mangled the frame during a tense Davis Cup match against Sam Querrey of the United States.
Since it was the first violation of the match, it was only a warning. No points were deducted and Cilic did not exchange any words with Ramos.
Ramos was also the umpire who gave Serena Williams three code violations in her straight-set loss to Naomi Osaka during last weekend's U.S. Open final. The American great argued she wasn't being treated the same as some male players.
The normally collected Cilic lost his cool after committing a series of uncharacteristic errors late in the third set against Querrey.
After winning the opening set, Cilic wasted a 6-1 lead in the second-set tiebreak.
Querrey, who played in place of Steve Johnson, won the third set to take a two sets to one lead.
Croatia leads the best-of-five semifinal 2-1.
Croatia's Borna Coric is due to face Frances Tiafoe in a potentially decisive fifth rubber.