When Robbie Lawler and Rory MacDonald wrapped their epic battle for the welterweight title at UFC 189, both men were bloodied and battered.

The fight holds a place among the most brutal and entertaining fights in UFC history and the back and forth action had fans wondering how close referee “Big” John McCarthy was to stopping the bout at various points.

McCarthy spoke to that during a recent appearance on MMAjunkie Radio and said that there were really no points where he thought about stopping the fight because of damage Lawler had suffered on his way to a fifth-round TKO win.

“Everyone loved that fight, and they should have,” McCarthy said. “But, everyone was concerned about me stopping the fight, either in the third round or the fourth round – stopping the fight with Robbie being hurt and Rory being the winner. Everybody has asked, ‘How close were you to stopping the fight?’ It’s like no one understands. I was never really that concerned about Robbie Lawler in that fight. I was very concerned with Rory MacDonald. From about the fourth minute of the first round on.”

McCarthy’s concerns in the bout came down to lasting impact more than superficial damage, such as Lawler’s badly split lip.

With MacDonald’s nose broken in the first round, the concern became blood going into his lungs.

“What I’m seeing when I’m watching Robbie and Rory – Rory is, in the first round, landing more punches, but they’re not real hard,” McCarthy said. “Robbie is not throwing a lot, but when he’s landing shots they are thudding shots. They are heavy. And then he ends up breaking his nose in the first round. I watch Rory and he starts doing what we call aspirating blood.

“As he’s breathing through his mouth, he sucks in more air as he gets more tired – now he comes into the second round and third round he gets a cut in his mouth. And he’s got a cut that’s bleeding into his mouth. In the third round he’s really sucking a lot of air. When he goes after Robbie and he’s hurting Robbie, that’s great, but he’s sucking these little droplets of blood that are now being aspirated. They’re not going down into his stomach, they’re going into his lungs and they’re stopping what his lungs can do as far as dissipating that oxygen to his muscles. This is the thing that I’m worried about. This is what I’m watching.”

Eventually, the damage accumulated to the point where a single shot from Lawler was too much for MacDonald to take, leading to the stoppage at the 1:00 mark of Round 5.

McCarthy said that he was waiting for that moment when the damage, fatigue and restricted ability to breathe would catch up with MacDonald. Something that explains where his focus was placed during the war.

“90 percent of that fight I was watching Rory.”

For complete coverage of UFC 189, check out the UFC Events section of the site.