FANS are convinced Tyson Fury was concerned that his brother Tommy had not done enough to beat KSI.
The boxer controversially edged the YouTuber on points after a laboured performance.
KSI has claimed the result is a "robbery" and has vowed to appeal the decision after Fury won the close encounter despite being docked a point for an illegal blow.
As the results were read out at the end of the sixth round, the cameras panned to a nervous-looking Gypsy King.
The WBC heavyweight champion was spotted with pursed lips as he looked on ringside.
Relief was then shown as Fury jubilantly burst into wild celebration when his younger sibling's victory was confirmed.
READ MORE IN BOXING
Tyson's reaction has made fans convinced that he was uncertain Tommy had done enough to win.
One said: "Even Tyson Fury thought he lost you could see it on his face before they told Tommy won."
Another added: "KSI definitely won that match… Tyson Fury didn’t even flinch to celebrate with Tommy."
A third commented: "It's obvious from his celebration he is surprised."
Most read in Boxing
FREE BETS - BEST BETTING OFFERS AND BONUSES NEW CUSTOMERS
More reacted: "He knows God damn well KSI won that, he ain’t safe after this appeal."
Tommy's father John seemed less worried about the decision, saying post-fight: "We did what we had to do. KSI didn't wanna fight, he wanted to hold all night, he was smothering Tommy's work.
"[The point deduction] was bulls***.”
After victory, Tommy claimed he was done with crossover boxing and will not enter in a rematch with KSI.
However, he then called out both Logan and Jake Paul.