With all sports thriving on gripping rivalries, the future of men's tennis looks to have an exciting future with Daniil Medvedev and Stefanos Tsitsipas.

On Friday, Russian second seed Medvedev beat fourth seed Tsitsipas 7-6 (7-5) 4-6 6-4 6-1 in their Australian Open semi-final.

It is the second successive year that Medvedev has beaten Tsitsipas in the Melbourne last four, extending his dominant record over the Greek to seven wins from their nine career meetings.

The opening three sets were high quality, packed with gripping rallies as each player tried to gain the upper hand.

But attention also turned to a dramatic outburst from Medvedev, who complained his opponent was receiving on-court coaching - which is not allowed - from his father Apostolos.

"I wasn't getting coaching," insisted Tsitsipas. "It's funny. I don't pay attention to the stuff.

"I know players like to do this stuff to throw you off mentally. It could maybe be a tactic. It's alright. He's not the most mature person anyway."

Tsitsipas, 23, played at a high level in the opening two sets, with Medvedev's rant at umpire Jaume Campistol coming during the changeover after he lost serve to go 5-4 down in the second set.

Medvedev demanded the official issue a code violation to Tsitsipas, saying he thought his opponent might have been taking instructions from his father in Greek.

Afterwards, Medvedev said he wasn't accusing Tsitsipas of cheating.

"Not at all," said Medvedev. "I got broken, I got a little bit mad. I thought the referee could do a little bit better with the crowd, just to say: 'Quiet, please'.

"Before every return his father was talking Greek. I don't know what his father is saying. Maybe he's just saying: 'Let's go, next point'. It's completely allowed. There is no problem with it.

"But he's saying something in Greek just before I return, and I feel like he's even telling him where to serve. I don't know. I don't know Greek."

After airing his grievances and surviving break points in the opening game of the third set, Medvedev settled down back into the match.

He retook the lead in what proved to be the final game of the third with his first break opportunity of the set.

At the start of the fourth set, Greek umpire Eva Asderaki-Moore was positioned underneath where Tsitsipas's coaching team were sat. Moments later, Campistol did issue a violation code for on-court coaching.

From that point at 1-1, Tsitsipas did not win another game as he quickly faded away.

Afterwards, Tsitsipas said he felt he is being unfairly targeted by umpires as a result of his reputation.

"I'm used to it. I feel like I've got a few in the past, and the umpires are always paying attention to my box, never paying attention to the opponent's box," he said.

"I feel I have been a victim of that for a long time now.

"I don't think the referees will ever understand that I cannot hear anything when I'm playing."

Medvedev stressed his complaints were "nothing against Stefanos", while Tsitsipas called his opponent a "great competitor" and said he respected how the Russian could run "like a marathon runner".

Although Tsitsipas added he was unsure how sustainable that style will be - pointing out the "huge impact" it has had on the bodies of other Grand Slam champions - it seems the pair are destined for a long, fraught and entertaining rivalry.