Australian open 2021: Tennis hot head Nick Kyrgios implodes again at Murray River Open

Tennis bad boy Nick Kyrgios has continued his fiery start to the new year with his second on-court tantrum in three days. 

Kyrgios struggled with a knee injury throughout his 6-3 6-4 third round defeat to Borna Coric at the Murray River Open and revealed after that he's been struggling with his knee for over four months. 

The 25-year-old received a warning for an expletive-laden tirade at 4-4 in the second set as f-bombs were the order of the day. 

After losing his service game, he smashed his racquet and threw it into the empty stands. The chair umpire had no option but to award a point penalty for unsportsmanlike behaviour. 

It was Kyrgios's second meltdown in just three days after he took exception to a time violation call in his previous match. 

The Canberra native voiced his concerns over player welfare after the match and believes the disrupted build-up for the year's first Grand Slam, which starts on Monday may see others struggle as well. 

"I think everyone's got a bit of a question mark over the physical side," Kyrgios says. "Anyone can get injured here and there because no one has played a best of five set match in a long time.

"It's not easy to just turn around and prepare for an event just like that. It's not like a tap.

"I thought I did everything I could this week. I won a couple of matches, I had a lot of court time and practised every day, as well.

"I think I'm ticking the boxes, I think I'm giving myself a chance."

The year's first Grand Slam - the Australian Open - begins on Monday.