"It was absolute mayhem. We were about 10 rows back from where it all happened and we couldn't really believe what had just gone on, it was just crazy.
"It broke out in the crowd — and then on the other side of the stadium it broke out in the crowd [too]. There was chairs getting thrown, it was just going crazy.
"We went downstairs to walk out and all through the back of the stadium there was fights through the hallways, into the bar area. There were glasses and bottles getting thrown.
"We went back and sat in our chairs for an extra half-hour until it cooled down. Absolutely crazy."
Lewis, who spent 12 seasons with the Panthers before moving to Cronulla in 2013, is overseas with a group of friends, including some from Penrith.
"Let me guess a couple of boys from Penrith going 'this isn't anything unusual'," joked The Grill Team host Matthew Johns.
"Just like a Saturday night at The Pioneer!"
"You know what the boys are like they all wanted to go out there and ... I can't get into too much detail because I'll get in trouble," Lewis responded. "But the Penrith boys were on fire."
McGregor was forced to tap in the fourth round of the fight after the champion locked in a rear-naked choke to complete a dominant performance.
"I love Conor McGregor, I'm a massive fan of him," Lewis said.
"I was sitting there when the fight was about to start, I was shaking for him because I just didn't want him to lose. You hate to see a champion go down.
"But when Khabib got in the ring, you knew he was there to fight and he just executed exactly what he said he was going to do at the press conference. He was going to wrestle him and tire him out and then go toe-to-toe with him. And he pretty much did that.
"That beautiful right hook he got him with set the tone of the phone. After that Conor looked a little rattled from where we were sitting."
Lewis attended an NFL game on Monday morning and was planning to catch an NBA game featuring LeBron James and the LA Lakers to complete an epic sporting week.
"I love Conor McGregor, I'm a massive fan of him," Lewis said. "I was sitting there when the fight was about to start, I was shaking for him because I just didn't want him to lose. You hate to see a champion go down.
"But when Khabib got in the ring, you knew he was there to fight and he just executed exactly what he said he was going to do at the press conference. He was going to wrestle him and tire him out and then go toe-to-toe with him. And he pretty much did that.
"That beautiful right hook he got him with set the tone of the phone. After that Conor looked a little rattled from where we were sitting."
Lewis attended an NFL game on Monday morning (AEST) and was planning to catch an NBA game featuring LeBron James and the LA Lakers to complete an epic sporting week.