Andrey Rublev was defaulted from his semifinal at the Dubai Championships on Friday for yelling in the face of a line judge, allowing Alexander Bublik to advance to the final.
The second-seeded Rublev erupted after Bublik won a point to take a 6-5 lead in the deciding set.
The Russian player, who is ranked No. 5, immediately pointed to the baseline, walked to the line judge, leaned over and shouted in his face.
ATP supervisor Roland Herfel came to the court accompanied by a Russian speaker, who said Rublev swore in his native language.
Rublev responded: "I was talking to him in English."
But umpire Miriam Bley defaulted Rublev, after which the seventh-seeded Bublik said, "I'm OK to continue" with the match.
"I highly doubt Andrey said something crazy," Bublik told reporters. "He's not this kind of guy. But I guess that's the rules. That's what they did, they just follow the procedure."
"There's not much to say. With all due respect, it was a great match and both of us deserved to win. The crowd was there and we could have played one of the greatest matches against each other. It's a pity it ended like this."
Bublik won 6-7 (4), 7-6 (5), 6-5 and will face Ugo Humbert in the final after he defeated top-seeded Daniil Medvedev 7-5, 6-3.
The default means Rublev will lose his prize money and ranking points earned at the tournament. Rublev won the hard-court tournament in 2022 but lost to Medvedev in last year's final.
Bublik also was penalized during the match for an outburst. Having drawn level after a tense second set, Bublik smashed his racket and received a code violation for swearing after he was broken at the start of the third set and shouted at the umpire.
In the second semifinal, the No. 4-ranked Medvedev was undone by Humbert for the third time in four matchups. Humbert was aggressive, and his left-handed serve sent the Russian player wide to open up the court.
"I played the perfect match today," Humbert said.
The Frenchman's confidence has been high since he won the Marseille title three weeks ago. That was his was fifth career title. He has never lost a final.
The big-serving Bublik is looking for his fifth singles title. The Kazakh player won Montpellier last month.
The Associated Press and Reuters contributed to this report.