Dusan Vlahovic told reporters that allegations he was having an affair with the wife of one of his international team-mates was "absurd".
Juventus striker Vlahovic, 22, has played just 24 minutes at the World Cup after suffering an injury while on club duty. He sat out the 3-3 draw with Cameroon, which left Dragan Stojkovic's side needing a win against Switzerland in their final group game to progress to the knockout stages in Qatar.
Reports on the continent have alleged the former Fiorentina star has been having an affair with the wife of World Cup colleague Predrag Rajkovic. However, the striker made a point of addressing the claims ahead of a crucial game for his national side.
"I am sorry to have to start the press conference in the World Cup this way, but I have to talk about it because this is my name being bandied about," Vlahovic said, as reported by Football Italia. "What we all read and hear about, there's no need to comment on something so absurd.
"Evidently these people are bored and have nothing better to do because they are frustrated or angry, but working against the national interest of the team at the moment is obviously their main job right now. We are more united than ever and the atmosphere in the squad has never been better.
"These stories are ridiculous, I just want to protect my name and my integrity, so I will take legal action if necessary."
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Vlahovic came off the bench in Serbia's first World Cup match, a 2-0 defeat against Brazil. He wasn't involved against Cameroon, however, with Stojkovic's side failing to hold onto a 3-1 lead.
He has scored eight goals for club and country this season, including one against Bahrain in a World Cup warm-up friendly. The frontman also netted four times in qualifying as Serbia pipped Portugal to top spot in their group.
"It's not the first time this has happened," he said of the allegations. "I would've hoped that people would support the team before such an important match, but instead we are forced to talk about things that have nothing to do with it.
"These are people with empty CVs who achieved nothing, but they will certainly not get extra attention off my name. They have always been small people and prove it day by day."
It is the second successive World Cup in which Serbia have been drawn in the same group as upcoming opponents Switzerland. When they met in 2018, goals from Granit Xhaka and Xherdan Shaqiri gave the Swiss a crucial victory after an early opener from Aleksandar Mitrovic.
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