BOSTON — Stipe Miocic set the UFC heavyweight record with his third straight successful title defence, turning the anticipated slugfest against Francis Ngannou into a methodical ground-and-pound bout to win the main event of UFC 220 at TD Garden.

Miocic won 50-44 on all three scorecards early Sunday and was never seriously tested by the raw but unrefined Ngannou.

Miocic (18-2) and Ngannou (11-2) had UFC fans buzzing with perhaps the most-hyped heavyweight title bout since Brock Lesnar was the class of the division. Both fighters have a violent history of finishing off their foes within two rounds and Ngannou was coming off a nasty knockout win just seven weeks ago.

Both fighters were winded by the third round and Ngannou looked sleepy as he whiffed on a few blows in the fifth.

For a round, the fight seemed like it could reach epic slugfest proportions. Miocic and Ngannou tagged each other several times in the first, leaving each fighter staggered and seemingly on the brink of trouble.

“He’s a tough dude. Caught me in the first round but I took control,” Miocic said.

The fight never really picked up from there. Miocic spent the rest of the fight just banging away as Ngannou mostly covered up, hoping for one last desperate knockout punch.

He never found it.

“I think I underestimated (him) a little bit,” said Ngannou, whose rise from homeless to heavyweight contender captivated a sport eager for a new star.

Miocic beat Fabricio Werdum to win the heavyweight title in May 2016, and followed with wins against Alistair Overeem, Junior dos Santos and now Ngannou to slug his way into the record book.

Miocic could lay claim as UFC’s greatest heavyweight.

“I mean I’m not the scariest, but I’m the baddest,” he said.