Oleksandr Usyk says he was advised by his trainer not to knock out Anthony Joshua in the world heavyweight title clash on Saturday night.
Usyk beat Joshua by unanimous decision after a sensational performance to claim the IBF, WBA and WBO belts at the Tottenham Hotspur Stadium in front of more than 60,000 fans.
"I had no objective to knock him out because my trainer, in my corner, pushed me not to do that," Usyk said after.
"In the beginning I hit him hard and tried to knock him out.
"But then my trainer said: 'Just stop, and do your job'."
Usyk hurt Joshua in the third round with an accurate left hand, caused substantial swelling around his eye, then came close to a 12th-round stoppage.
But he warned: "You didn't see the best Usyk. I can be much better."
Usyk reflected on becoming only the third boxer ever to become a world champion at cruiserweight and heavyweight: "This means a lot to me.
"The fight went exactly the way I expected it to go.
"There were a couple of moments where Anthony pushed me hard. But nothing special."
Usyk is now undefeated in 19 after winning an Olympic gold medal. He was undisputed at cruiserweight and is only missing Tyson Fury's WBC belt to match that accomplishment at heavyweight.
Vitali Klitschko, Usyk's fellow Ukrainian and a former heavyweight champion, said from ringside: "Excellent fight. Very clever. Oleksandr did a perfect job.
"After Wladimir Klitschko he is the second heavyweight champion to take [more than one] belt."
Vasiliy Lomachenko, the pound-for-pound great, said: "It was a great performance and a historic fight. Now, he is in history."