Warning: this article contains some confronting footage.

Boston Celtics small forward Gordon Hayward has sustained an absolutely horrific ankle break, less than six minutes into the first game of the regular NBA season.

Play stopped dead after Hayward went up for an alley-oop against the Cleveland Cavaliers, only to fall awkwardly on his left leg.

Players on both sides walked away in shock at the severity of the injury. Again, heads up: the footage is full-on.

The 27-year-old was stretchered off the court to receive treatment, as Cavs legend LeBron James offered his support for his injured opponent.

The Celtics have confirmed that Hayward suffered a fractured ankle. It’s highly likely that Hayward, who only signed for the Celtics from the Utah Jazz in July, will be sidelined for the remainder of the season.

Oklahoma City’s Paul George, who suffered his own wince-inducing leg break in 2014, offered his support for Hayward on social media.

Bloody hell. All the best, mate.

Source: ESPN
Image: Gregory Shamus / Getty