Daniil Medvedev, the young Russian who knocked out Stan Wawrinka, is facing the prospect of heavy punishment after being forced to deny that he made an accusation of bias when he threw money at the umpire’s chair following the conclusion of his ill-tempered second-round exit.

Two days after delighting Centre Court with a nerveless win over Wawrinka, the 21-year-old found himself in hot water when he reacted angrily to a series of controversial calls during his defeat to Belgium’s Ruben Bemelmans, appeared to ask the court supervisor to remove Mariana Alves as umpire late in the fifth set then emptied his wallet of loose change moments after losing 6-4, 6-2, 3-6, 2-6, 6-2.

Wimbledon officials are likely to take a dim view of Medvedev’s conduct, despite his insistence that there was no deeper meaning to his behaviour, and he could be hit with a hefty fine.

Britain’s Heather Watson received the second-largest ever single fine in the tournament’s history last year – $12,000 (£9,043) for smashing her racket into the grass – while the record remains the $20,000 Fabio Fognini received for unsportsmanlike behaviour in 2014. The Italian was sanctioned for “damaging the court” but also received an extra fine of $7,500 for abusing a tournament official and making an obscene gesture to his opponent.

Medvedev, who visited the referee’s office after completing his media duties on Wednesday night and said that he would apologise to Alves personally if he sees her, admitted it will be his fault if he has fallen foul of the authorities. There is a chance that his embarrassed demeanour in an apologetic press conference could lessen the damage.

However, he was at a loss to explain why he threw money at Alves’s chair. “I was just frustrated, so it has no meaning,” he said. “I haven’t thought about it.”

Medvedev, who was defaulted from a tournament in the US last year after questioning the impartiality of an umpire, was at pains to stress that he was not insinuating bias on the part of the official. “It would be really stupid,” he claimed. “It was stupid, but it was not like this. It was just that I was packing my things and I saw my wallet. In the heat of the moment I did a stupid thing. I was ready to leave the court, but that’s what happened. I don’t even remember what the coins were.”

But the world No49 could not justify his behaviour and said that he had immediately regretted it. His unhappiness grew after squandering a 2-0 lead in the fifth set and his frustration boiled over when he found himself trailing 5-2 at a changeover. Docked a point after arguing with Alves, he called for the supervisor.

Asked whether he requested Alves’s removal, Medvedev replied: “I don’t actually remember what I said. It was a long match … very hot out there.”

It represented an unsatisfactory end for the Russian, who had never won a grand slam match before beating Wawrinka, the No5 seed and US Open champion.

“I was disappointed with the result,” he said. “It was frustrating after a big win. The match was not going well for me. In the heat of the moment, I did a bad thing. I apologise. Sometimes you are unhappy with the call. Sometimes it’s in your favour. It happens.”