Aus Open: Tennis stars pay tribute to Kobe Bryant

'He was one of the people who was really there for me to give me some very valuable advice and guidelines to kind of believe and trust in myself, trust the process that I'll be back.'

Australian Open champion Novak Djokovic led the tennis world in mourning for "mentor" Kobe Bryant on Monday after Melbourne Park awoke to the news that the NBA great had died in a helicopter crash along with his daughter and seven others.

Djokovic had spoken fondly of his relationship with the former Los Angeles Laker in an interview at the weekend and the 16-times Grand Slam champion signed off his Tweet of condolence with the words: "RIP my friend".

"My heart truly mourns over the news today. Kobe was a great mentor and friend to me," the Serbian wrote.

"You and your daughter will live forever in our hearts. There are not enough words to express my deepest sympathies to the Bryants and every family suffering from this tragedy."

Multiple Grand Slam champion doubles pairing and Lakers fans Bob and Mike Bryan played their final match at Melbourne Park before retirement with yellow tape on the backs of their legs marked with Bryant’s shirt number, 24, and nickname, Mamba.

Djokovic's great rival Rafa Nadal also joined a cavalcade of top players in expressing his condolences, declaring his "shock" at the news of the death in California of one of the NBA's all-time greatest players.

"I woke up this morning with the horrible news of the tragic death of one of the greatest sportsman in the world," the Spaniard wrote.

Nadal, chasing his 20th Grand Slam title, plays his fourth round match later on Monday against Australian Nick Kyrgios, who is a massive NBA fan.

Djokovic said at the weekend Bryant had helped him when he was battling an elbow injury and was struggling to "mentally and emotionally handle" working his way back to the top.

"He was one of the people who was really there for me to give me some very valuable advice and guidelines to kind of believe and trust in myself, trust the process that I'll be back," he told ESPN.

"I'm very grateful to him for being there for me, for being very supportive. I love Kobe, who doesn't? He's an amazing guy and one of the best basketball players and athletes of all time."

Djokovic was clearly not alone in receiving support from Bryant, with 2008 Australian Open champion Maria Sharapova, who was knocked out in the first round this year, also stunned by the news.

"This is incredibly difficult to process," wrote the Russian.

"I will never forget your generosity, and the time you set aside in some of my most difficult moments. I am forever grateful. My heart is with you and your beautiful family."