Boston Celtics forward Marcus Morris thrived when the lights were the brightest, holding postseason leading scorer LeBron James to a playoff-worst 15 points and seven turnovers on Sunday afternoon.

Morris has been a willing and skilled defender throughout his NBA career, but upon landing with the Celtics this summer, he finally found the church where defense is a religion, film is bible, and a next-man-up mentality has been the singing choir throughout the time Brad Stevens, the high priest of this church, has been at the helm.

The Philly native has studied film incessantly, looking to learn from others' mistakes and capitalize on their weak areas, looking forward to this Eastern Conference Finals matchup against the Cleveland Cavaliers superstar.

But why look to the toughest task? To soak up the most pressure-filled job in basketball throughout a seven-game series?

“Because I’m a competitor,” Morris said, according to Candace Buckner of The Washington Post.

Morris learned a thing or two from James' prior series against the Indiana Pacers and the Toronto Raptors, but they were not pleasant.

“Them dudes can’t guard. That’s what I did pick up,” Morris said, bluntly.

Morris did pick up three fouls in the first half, but it didn't deter him from hounding James for 24 plays. During those moments, Morris held James to 2-of-6 shooting and a mere five points, according to ESPN Stats & Info.

The 6-foot-9 forward outscored James with 21 points and 10 rebounds, hitting 7-of-12 from the field and an efficient 3-of-4 from deep.

Morris praised his team during the post-game press conference, which played a huge part in his defensive stunts — knowing another capable defender was back there to help him.