Alexander Zverev's post-match interviewer at the Australian Open humbly apologised after the tennis star jokingly pointed out that she had a croaky voice during their post-match chat.

Andrea Petkovic, the former German women's singles player, has spoken to dozens over players over the years after turning to media work following her retirement.

But her conversation with her compatriot Zverev was perhaps more difficult than she would have anticipated, after she struggled to get her words out when speaking to the 27-year-old on Sunday.

When asking how the world No. 2 changed his tactics during his four-set victory over Ugo Humbert, Petkovic's voice had a raspy quality to it - and Zverev was quick to notice.

She began: "Sascha, into the quarter-finals of the Australian Open once again... incredible performance against a top-20 player in Ugo [Humbert]. You got a bit complicated, so you changed a bit your style, what did you think our tennis today?"

After a brief pause, Zverev replied: "I think that you party too much, your voice is gone!"

Clearly embarrassed, Petkovic issued a grovelling apology: "I'm so sorry, I apologise! I was yelling at you so much [during the match] that I lost my voice!"

"So you were yelling at me, or for me? Which one is it?" Zverev asked, to which she replied: "For you!"

In the end, the tennis star chose to forgive her: "Alright, I'll let you go then," he said with a smile.

"He's a tough player, especially in the last months, he did so many steps forward," Zverev continued, speaking about Humbert. "He made the final of his first [ATP] 1000 event. I think he played an incredible year."

But the hilarious awkwardness didn't stop there. When Petkovic interjected that Humbert lost to him at the Paris Masters in November, he pretended to get riled up.

"OK, he lost to me. But that was the not the point!" Zverev said while laughing. "Why are you making it awkward? I don't know, I can't talk to you!"

The conversation was playful in context - both were smiling at each other during the entire exchange - and there was no bad blood between the pair.

Indeed, Petkovic and Zverev go back a long way. The pair played together at the Hopman Cup in 2017 in the mixed doubles event.

It seems their relationship is friendly enough for them to share a bit of banter on the court, and the crowd seemed to enjoy the exchange as choruses of laughter emanated from the stands.

Zverev will need to put his gameface back on in a couple of days' time when he faces Tommy Paul in his quarter-final clash on Tuesday.