Defying expectations, Douglas would knock out Tyson in the 10th round to claim the WBC, WBA, and IBF titles.

Douglas fought just three times in 1986, defeating former champion Greg Page and fringe contender David Jaco in two of the bouts.

This earned him a shot at the International Boxing Federation championship that was stripped from Michael Spinks for refusing to defend it against Tony Tucker.

Douglas started well against Tucker and was ahead on points, but he ran out of stamina and suffered a technical knockout in the tenth round.

After the Tucker defeat and a series of disagreements, James split with his father; the Douglas family was shattered.

Many thought it was a tune-up for Tyson before a future mega-fight with undefeated Evander Holyfield, who had recently moved up to heavyweight after becoming the first undisputed world cruiserweight champion in the history of that weight class.

Douglas's mother, Lula Pearl, died of a stroke 23 days before the title bout at the age of 46.

Douglas, who had trained hard, surprised the world by dominating the fight from the beginning, using his 12-inch reach advantage to perfection.

Rather, Tyson set his feet and threw big, lunging hooks in efforts to stop Douglas with one punch.

By the fifth round, Tyson's left eye was swelling shut from Douglas's many right hands and ringside HBO announcers proclaimed it was the most punishment they had ever seen the champion absorb.

They had not brought an endswell or an ice pack to the fight, so they were forced to fill a latex glove with cold tap water and hold it over Tyson's swelling eye.

[5] Tyson came out aggressively in the ninth round and continued his attempts to end the fight with one big punch, hoping Douglas was still hurt from the eighth-round knockdown.

So when I had seen him looking around for that mouth piece I knew he was really hurt.”[7] Douglas's joy over the victory soon turned to confusion and anger as manager John Johnson informed him in the dressing room that Tyson and Don King were lodging an official protest about the referee's knockdown count in the eighth round.

[8] Although the IBF immediately recognized Douglas as its champion, the WBA and WBC initially refused due to Tyson's protest.

[9] However, Tyson withdrew his protest four days later amid worldwide public outcry and demands from boxing commissions around the world, and Douglas was officially recognized as undisputed heavyweight champion.

[10][11] While still champion, Douglas appeared on the February 23, 1990 episode of the World Wrestling Federation's The Main Event III, as special guest referee for a rematch between Hulk Hogan and "Macho King" Randy Savage.

Originally, Tyson was scheduled to be the guest referee, but following the upset, the WWF rushed to sign on Douglas for the event.

Douglas merely lay flat on his back, motionless and disoriented, as referee Mills Lane stopped the fight.

Douglas was unable to continue after a five-minute rest period and was consequently awarded the win by disqualification (on account of Monaco's illegal punch).

On February 23, 1990, Douglas made a special appearance as a guest referee on WWF's The Main Event III in a match-up between Hulk Hogan and "Macho Man" Randy Savage.

Singer songwriter Brandon Flowers used the childhood memory of watching the seemingly invincible Tyson lose, as the motivation for a song that's about "me and my family, and the way I’m perceived by my kids.

[4] Although Douglas filed for divorce from Paige on April 20, 1990, the couple reconciled and as of 2015 are still married, raising four sons about 25 miles (40 km) from his hometown of Columbus, Ohio.

[15] Douglas has helped raise money for his hometown, donating $10,000 to the Police Athletic League shortly after his bout with Tyson, and establishing a charitable effort in his own name.