Argentine player Olivo Renzo has written a public letter complaining about the behavior of his opponent, Andrey Rublev, during their match at the Moscow Challenger tournament.

The 23-year-old Renzo, who is currently ranked No. 164, put up his letter in a Twitter post, saying the Russian teenager had attempted to intimidate him and nothing had been done.

Hola a todos me gustaría dejarles esta carta para los interesados del tenis y también al ATP @ATPWorldTour Gracias! pic.twitter.com/b2JSb9AvlO — renzo olivo (@renzolii) June 11, 2015

In a translation of the letter by BA Tennis World, Renzo said, "As some of you know, today I lost in the second round of the Moscow Challenger and I would like to make a public complaint and thus also have possibility of it getting to the ATP. I am disappointed with what happened during today’s match, in which the rival played against the rules a couple of times, and threatened me. I am disappointed because the umpires don’t make the decisions that they should. We also make mistakes, and we pay for them, literally. However, the umpires don’t…"

Renzo went on to say that Rublev's behavior went beyond the kinds of complaints that can sometimes be expected in matches.

"Breaking the rules is something that’s wont to happen now and then. I admit to having made mistakes, too, and to have broken rules sometimes. But to receive threats during a match, when the rules state that the match should be suspended, this I don’t tolerate."

Renzo did not specify exactly what had occurred. The Argentine added that the umpire had been "very conscious" of what had happened, but did nothing. In addition, he also said that someone in the crowd grabbed him following the match but others were able to fend them off.

At the ATP tournament in Barcelona, Fernando Verdasco also complained about Rublev following his defeat to the 17-year-old qualifier, saying "I am surprised how rude he is for a 17-year-old," adding, "He shows little respect for his opponent." Verdasco also did not explain what had prompted his complaint.

Rublev responded by saying at the time, "I didn't say anything bad about him but sometimes...you show your emotion."

The Russian has not issued a response to the latest accusation against him.