INGLEWOOD, Calif. — Rory MacDonald gave a four-word answer last month when he was asked on a Reddit AMA if he thinks Robbie Lawler was on performance-enhancing drugs when the two met at UFC 189 for the UFC welterweight title in 2015.

“I’m convinced he was,” MacDonald said.

MacDonald explained that conclusion in an interview with MMA Fighting on Tuesday. MacDonald, who now fights for Bellator MMA, said he believes the way in which Lawler pushed through in the all-time classic battle was unnatural. Lawler won the fight by fifth-round TKO in a bout in which MacDonald was ahead on the scorecards.

“He never slowed down,” MacDonald said. “I would hurt him and his output was high, high, high and he never really lost power and endurance. He just kept the pace and kept the power no matter how hurt or tired he was. He always was recovered very fast. It made me very suspicious.

“Obviously, I think Robbie is a tank of a person. He’s got that fire and that will and the rage and that anger in him that burns and pushes him through those hard moments. He’s an absolute warrior. I’m not disagreeing with that. But I do believe he was taking some sh*t.”

MacDonald, 28, referenced what he believes to be suspicious findings from Lawler’s drug test in relation to that fight to back up his feelings. Lawler did have high Luteinizing Hormone in one test and other irregularities, but the levels were normal in subsequent screens. Lawler did not fail the drug test or any other by USADA or World Anti-Doping Agency standards.

“The Red King,” who challenges Douglas Lima on Jan. 20 here in Los Angeles for the Bellator welterweight belt, said he has heard things tying Lawler’s former gym, American Top Team, to performance-enhancing drug use. MacDonald got into a Twitter spat with Yves Edwards, a longtime ATT veteran and former teammate of Lawler, after his Reddit comments.

MacDonald wants to make it clear that he doesn’t think everyone at American Top Team is cheating.

“I didn’t call so and so and so and so someone who was on performance-enhancing drugs,” he said. “I don’t have an issue with whatever. Someone asked me, ‘Do I think Robbie Lawler is on steroids?’ Yeah, I do. That’s it.”

Lawler’s manager Dave Martin didn’t respond to a request to address MacDonald’s comments.

Lawler, who has beaten MacDonald twice, has passed all 21 USADA drug tests that he has taken dating back to 2015, per the agency’s website. UFC 189 was right after the UFC brought in USADA to run its anti-doping program.

MacDonald said he’s not upset with Lawler and not complaining about the loss two years ago. He just believes what he believes based on his experience.

“I’m totally not crying about it,” MacDonald said. “If you’re gonna ask me, do I think Robbie Lawler takes performance-enhancing drugs? Absolutely, I do. And I absolutely think he was on something when we fought.”