'Andy will always be a titan'

'Remarkable discipline for training, competition, sacrifice, perfection, a little crazy but a legend of a bloke. Bravo Andy'.

Former World No 1 and three-time Grand Slam champion Andy Murray announced on Friday that this year's Australian Open could be his last tournament as a professional.

• Tearful Andy Murray may retire after Australian Open

Here are reactions to Andy Murray's announcement:

FORMER WORLD NUMBER ONE BILLIE JEAN KING

'@andy_murray You are a champion on and off the court. So sorry you cannot retire on your own terms, but remember to look to the future'.

'Your greatest impact on the world may be yet to come. Your voice for equality will inspire future generations. Much love to you & your family'.

FORMER US OPEN CHAMPION JUAN MARTIN DEL POTRO

'Andy, just watched your conference. Please don't stop trying. Keep fighting. I can imagine your pain and sadness. I hope you can overcome this.'

'You deserve to retire on your own terms, whenever that happens. We love you @andy_murray and we want to see you happy and doing well'.

FORMER COACH DARREN CAHILL

'When you search for examples of 'emptied the bucket to be as good as they could be' there should be a picture of Andy Murray sitting under that quote.'

'Remarkable discipline for training, competition, sacrifice, perfection, a little crazy but a legend of a bloke. Bravo Andy'.

FORMER COACH DANIEL VALLVERDU IN RESPONSE TO CAHILL

'Whatever you think 'emptying the bucket' means... times that by 5 and that's who @andy_murray is. Thank you Andy - thank you for always being you. #1'

FORMER US OPEN CHAMPION ANDY RODDICK

'If this is true, I tip my cap to @andy_murray! Absolute legend. Short list of best tacticians in history. Unreal results in a brutal era... Nothing but respect here. I hope he can finish strong and healthy'.

'Just thinking out loud here. He deserves his moment to say goodbye at Wimbledon. He's too important to Great Britain and Wimbledon history to not have it'.

FORMER WORLD NUMBER TWO MAGNUS NORMAN

'If true. Feel down to the bone for Andy Murray right now. Amazing player, fighter, nr 1 and multiple GS champion. Deepest respect'.

FORMER GRAND SLAM DOUBLES CHAMPION PAM SHRIVER

'A male leadership voice that stands out and is outstanding during a challenging time for gender issues. Andy was able to reach #1 during the Federer Nadal Djokovic era making it the era of the big 4. My family is sending Andy all the love and support from Los Angeles. @JudyMurray'

FORMER US OPEN CHAMPION SAMANTHA STOSUR

'He's been a fantastic player, champion. I mean, he's been a massive advocate for women's tennis and women's sport in general. I know in the locker room whenever we hear him kinda stick up for us, we're like, 'Yeah, go Andy!''

AUSTRALIAN PLAYER THANASI KOKKINAKIS

'You're the man muzz'.

WORLD NUMBER 21 GRIGOR DIMITROV

'Tennis will come to an end for us all but the friendships will last a lifetime. What you've done for the sport will live on forever. I'm hoping for a strong and healthy finish for you, my friend! @andy_murray'.

FELLOW SCOT AND SNOOKER GREAT STEPHEN HENDRY

'Hard to read that @andy_murray being forced to retire because of injury, no doubt one of Scotland's greatest ever sportsmen'.

FORMER WORLD NUMBER ONE KIM CLIJSTERS

'My heart breaks listening to @andy_murray during his press conference... Hope he will make it through to Wimbledon and have the farewell he deserves. #greatguy'.

WORLD NUMBER SIX KEVIN ANDERSON

'My thoughts are with @andy_murray and I really hope we continue to see you fighting on court so you can retire on your own terms. Get well soon... Tennis is better with you'.

US DAVIS CUP TEAM CAPTAIN MARDY FISH

'The @andy_murray that I know will absolutely make it to Wimbledon to play his final tournament. Not many with more heart, effort in the history of the game. Was always a pleasure to share the court pal'.

WORLD NUMBER 38 JOHN MILLMAN

'Andy will always be a titan of our sport. A hero of mine throughout my career. A true warrior whenever he steps on the court'.

DALLAS MAVERICKS ICON DIRK NOWITZKI

'@andy_murray Legend!'

RUSSIAN PLAYER KAREN KHACHANOV

'Really sad to hear that @andy_murray. You are a true champion of our sport and great example for all of us! Stay strong'.