Daniil Medvedev should feel able to open up emotionally - if he wants to - in the wake of his US Open antics, says his close friend Andrey Rublev.

Former world number one Medvedev cut a desperate and disconsolate figure in a first-round defeat by France's Benjamin Bonzi, leading to concerns about his mental state.

The 29-year-old Russian was incensed by a perceived injustice when facing a match point in the third set, leading him to inciting a frenzied New York crowd and shouting at the chair umpire.

After eventually losing a chaotic match in a deciding fifth set, Medvedev brutally destroyed a racquet before sitting dejectedly on his chair for several minutes.

Medvedev's behaviour led to six-time Grand Slam champion Boris Becker advising the player to "seek professional help".

Asked if he would say the same to his friend, Rublev said: "I don't know - if he wants to change and needs help, he has me, a lot of other friends and family that will help him.

"But it's his life and his decision what he needs to do. Only he knows what is happening."

Rublev, however, is well placed to offer sage advice if Medvedev approaches him.

The pair have been close friends since meeting as aspiring young players in Russia, with Medvedev choosing 27-year-old Rublev to be a godfather to his children.

Rublev has also worked regularly with a psychologist to overcome his mental health struggles, which saw the 10-time Grand Slam quarter-finalist often aggressively attacking himself on court with his hands or racquet.

"I haven't spoke to him yet," said Rublev after winning his US Open first-round match on Monday.

"I think he needs to take some time because it was a tough loss for him, but I will text him.

"The year he's had in the Slams [winning only one match] has not been easy for him."