Russia's Andrey Rublev hits a return against Finland's Emil Ruusuvuori during their men's singles match on day four of the Australian Open.
CNN  — 

Andrey Rublev complained to the umpire in his second-round match at the Australian Open on Thursday about fans, who were holding a Ukrainian flag, of saying “bad things” to him.

Rublev was playing Finland’s Emil Ruusuvuori on the Show Court Arena when two fans sitting near to the 25-year-old Russian’s chair displayed a Ukraine flag.

“It was not about the flag,” No. 5 seed Rublev said after his four-set victory. “I said straightaway to the referee, it’s not about the flag, they can put any flag they want, I understand completely the situation.

“It was more that they started to tell me bad words and bad things.

“I said to the referee: ‘It’s not about the flag, but please can you tell them at least to not say bad words when I’m on the changeover.’”

Rublev has expressed his opposition to the ongoing war in Ukraine, signing ‘no war, please’ on a camera following his win in the Dubai Tennis Championship semifinal in February.

He also wrote ‘Peace, Peace, Peace, All we need’ after winning a match at the ATP Finals in November.

In light of the war in Ukraine, Russian and Belarusian tennis players have been permitted to play at the Australian Open but must do so “without flags or country recognition.”

On Tuesday, Tennis Australia announced that fans will no longer be allowed to bring the Russian or the Belarusian flag onsite at the Australian Open.

The decision comes after Ukraine’s ambassador to Australia “strongly condemn[ed]” the Russian flag being displayed in the stands at the grand slam.

The flag was seen during the first-round match between Ukraine’s Kateryna Baindl and Russia’s Kamilla Rakhimova in Melbourne.

An agency photo also shows the Russian flag on display in the stands during the first-round match between Daniil Medvedev and American Marcos Giron.

Rublev will next play No. 25 seed Dan Evans on Saturday.