Gervonta "Tank" Davis was a very interested observer in last Saturday's shocker, when Teofimo Lopez was upset by huge underdog George Kambosos at the Hulu Theater in New York's Madison Square Garden.

Kambosos dropped Lopez in the first round and secured a twelve round split decision to capture the IBF, WBA, WBC Franchise, WBO lightweights titles.

Davis will face a very big underdog on Sunday, when he defends the WBA "regular" lightweight title against Isaac Cruz in the main event of a Showtime pay-per-view card from the Staples Center in Los Angeles.

Davis believes Lopez overlooked Kambosos and viewed him as an easy defense. 

"Just a mistake he made," Davis told TMZ, "Going in there thinking someone's a slouch. That just taught me to never go in there thinking I won already and I didn't."

Back in June, the 27-year-old Davis (25-0, 24 KOs) impressed when he moved up to the junior welterweight limit of 140-pounds to score a knockout of unbeaten Mario Barrios to capture the WBA "regular" title.

Now he's back at the lightweight limit of 135-pounds and wants to impress against a very determined opponent in Cruz.

"I'm looking toward going in there and putting on a show. It's the biggest fight of my career," Davis said.

"Just be ready. I'm ready. Give the fans what they want to see."

Davis also made it known that he's not offended by the recent statements that were made by Kambosos, who referred to himself as the "best" lightweight fighter in the world.

"He's supposed to feel like that. I mean, he just won," Davis said. "Maybe he was in the heat of the moment.

"But, there's a lot of lightweights to show him that he's not the best."