Anthony Joshua loses WBA, WBO, IBF world heavyweight titles to Mexican Andy Ruiz Jr
Listen again to commentary on BBC Radio 5 Live Sports Extra from 06:00 BST
Callum Smith stops Hassan N'Dam to defend WBA world super-middleweight title
Katie Taylor beats Delfine Persoon to become undisputed women's lightweight world champion
So what happens next? Eddie Hearn, just as he told BBC Radio 5 Live, has confirmed in the post-fight news conference that there is a rematch clause for the pair to fight again in November or December?
But where will that happen? In the United Kingdom or will Andy Ruiz try to force it to stay in America? Could it even be held in Mexico?
#bbcboxing
Bookie Basher: New rumours that AJ had a bad cold/virus only literally on Thursday. May explain why he went out like a light once punched-with no defence/hunger at all! Million miles from previous performances we have seen. Ruiz wasn't that good- he was lucky as AJ gave away his belts!!
Zachary: Your new heavyweight champion Andy Ruiz Jr.
Chris: Looked like the school bully knocking out the school jock.
More from Frank Bruno, who speculates that Joshua might not have been in top condition...
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
Former European heavyweight champion Audley Harrison on Twitter...
Image source, .Text 81111 (UK only).
Where was Joshua's guard?! He was so open for so much of the fight. Unbelievably poor performance and reaction from the defending champion.
Jon Nichols, Poole
Unbeaten British cruiserweight Lawrence Okolie tweets his support for "his blood brother".
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
#bbcboxing
Peter Charles: I have always believed that AJ was over rated and that one cannot be a world class athlete when one is focused on one or two events a year. AJ is a charming man but he has lost the "Eye of the Tiger" and that desperate hunger to win and his management team should be ashamed as they allowed him to become distracted and a commercial pawn with no care about their man; sad and unforgivable.
DazInBlack: Seen this all before, muscle-bound boxers equals huge lactic acid build up and leaves you completely spent. Let’s face it they weren’t even great punches from Ruiz but AJ simply had nothing in the tank and if Ruiz was in better condition he could have got AJ out of there in the fourth round. Current heavyweight boxing is just so embarrassing.
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
Promoter Lou di Bella on Twitter...
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
Boxing legend George Foreman knows all about causing shocks, and being on the receiving end of them, has posted some very interesting tweets...
He writes: Big upset in boxing. Ruiz beat Joshua. Exciting time in boxing, rematch in London. Get ready England, win that title back.
"As they say, "don't believe the hype". Take anyone for granted and you lose. You walk around in a daze. Not becuase you lose, but because you believed all the print.
"AJ was talked into fighting a fighter he should have had more respect for. Ruiz has been a good fighter for a while.
"If Joshua continues to box, he will be better than before all that talent with true experience, he will make a better champion."
#bbcboxing
Safinator: There's only one Tyson Fury. Imagine would would happen if Joshua got hit by Wilder's big right. I have been saying since 2012 that Ruiz is one to watch and certainly has the fastest hands in the heavyweight division. Joshua is nothing but a heavily manufactured product. Ruiz had a 6 week training camp, 6 weeks!
Taz: Congratulations to Ruiz - great performance and well deserved winner. I've said it before and will say it again, AJ is nowhere near as good a boxer as he thinks he is. The AJ hype wagon is ludicrous - Wilder and Fury would both school AJ. I don't even see AJ winning a rematch in all honesty. I believe this is the beginning of the end for AJ.
Andy Ruiz Jr wins
Speaking to Sky Sports, Eddie Hearn said: "Anthony Joshua got sloppy and he never recovered. Tonight belongs to Andy Ruiz and it is a massive upset but AJ will be back. It is a very big upset and now we will find out what AJ is about and it will be a big rematch in the UK.
"He got hit on the top of the head and he will learn a lot from this. It's a massive blow for him and maybe this is what he needs and it is a must win fight for AJ now.
"Andy Ruiz Jr will believe he can win the rematch and AJ will have to rebuild. He is a true warrior and he has to use this hunger to bounce back."
Steve Bunce
BBC Radio 5 Live boxing pundit at Madison Square Garden
Eddie Hearn is a great promoter, all week he said one loss for Anthony Joshua changes everything, changes the landscape. We could have Luis Ortiz pull out, and we could have Ruiz versus Wilder (for all the world heavyweight titles) in September.
Former world heavyweight champion Frank Bruno tweets...
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
BBC Radio 5 Live Sports Extra
Just waking up? The news is going to stun you.
Anthony Joshua has lost for the first time in his career as American / Mexican Andy Ruiz, who only took the fight at six weeks' notice, takes Joshua's IBF, WBA, WBO and IBO world titles.
Fancy listening to the fight again?
It will be replayed in its entirety on BBC Radio 5 Live Sports Extra at 06:00 BST and again at 07:00 BST and again at 08:00 BST.
Andy Ruiz Jr wins
David Haye
Former world heavyweight champion on BBC Radio 5 live
If Anthony Joshua is healthy and fit as he says he is, then there is something wrong. He needs something in his camp that he didn't have.
I thought it was a fantastic night of boxing and unfortunately the Brit lost his belts, but this is why I love heavyweight boxing because anything can happen on the night.
Andy Ruiz Jr wins
Carl Frampton
Former world champion on BBC Radio 5 live
It will be interesting to see if there any changes made to his team because it is something that would not surprise me. I'm just glad I was here to witness it.
Tyson Fury tweeted that "these things happen" and told Joshua to "rest up, recover, regroup and come back".
Deontay Wilder, the only man other than Andy Ruiz to hold a world heavyweight title, isn't so kind. Wilder tweets...
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
Andy Ruiz Jr wins
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
Lennox is speechless. Lewis was no stranger to a shock defeat when he lost to Hasim Rahman in April 2001.
What happened next? Seven months later Lewis knocked out Rahman in four rounds in the rematch, then beat Mike Tyson, then beat Vitali Klitschko, so this defeat does not have to define Joshua's career.
Andy Ruiz Jr wins
Steve Bunce
BBC Radio 5 Live boxing pundit at Madison Square Garden
Anthony Joshua is not going to be able to get away with saying 'what a great fight that was - everyone was entertained'.
That is not good enough.
Image source, Reuters