08/19/2012 12:35 EDT | Updated 10/18/2012 05:12 EDT

Ronda Rousey needs only 54 seconds to submit Sarah Kaufman at MMA Strikeforce

SAN DIEGO - In the biggest fight of Sarah Kaufman's career, it was more of the same from Ronda Rousey.

Rousey submitted Kaufman in just 54 seconds Saturday at "Strikeforce: Rousey vs. Kaufman" with the same move she's used to finish every opponent in her career — an armbar — to defend the Strikeforce women's bantamweight title.

"I'm extremely embarrassed with my performance," Kaufman (15-2 MMA, 6-2 Strikeforce) said. "She's a world-class athlete and a world-class judo player and I knew it was going to be a tough fight. I just couldn't do what I wanted to do and land the strikes I wanted to land. I want to fight tomorrow — I'm ready to go."

Rousey (6-0, 4-0) came forward fast, looking to strike. She quickly had Kaufman pressed against the cage, and from there the 2008 Olympic judo bronze medal winner forced an easy takedown — right into her wheelhouse on the ground, where she could look for her favorite finishing move.

Kaufman did defend initially, then defended again as Rousey looked to re-cinch it. But the third time was the charm for the champion, who has now finished six pro opponents and three amateur opponents with the same move, all in the first round.

"Clearly I didn't want to hang out there. I didn't want to stay there," Kaufman said. "Once I lost my grip and she was able to pry my arm out, that was it, for the most part."

After the fight, Rousey called out former Strikeforce featherweight champion Cristiane "Cyborg" Santos, who currently is serving a steroids suspension. Santos has been reluctant to drop down to 135 pounds to meet Kaufman.

"I need to send out a challenge to Ms. Cyborg: I'm the champion and you should come down to 135 and let's settle this," Rousey told Showtime Sports.

The buildup hype on Rousey proved to be warranted. After winning the title against Miesha Tate in March, Rousey took the MMA world by storm. In the weeks and months leading up to the fight with Kaufman, Rousey got the bulk of the media attention, appearing nude on the cover of ESPN The Magazine, getting her own two-part Showtime special and appearing on popular programs like Conan O'Brien's late-night show.

But it was Tate who may have made a case to get back in with Rousey to contest the title.

On the preliminary card, Tate survived a kick to the face from Julie Kedzie in the third round and rallied to win by submission when she latched on to an armbar, forcing Kedzie to tap at 3:28 of the round.

Tate, of course, was submitted by Rousey in March with the same hold to surrender the bantamweight title. But Tate said she doesn't believe she has earned a quick trip back to challenge Rousey.

"At this point, everyone's saying it's Fight of the Night, but I'm personally not happy with my performance and I don't think it was a contention-worthy performance," Tate said. "I need to take a couple fights and I need a better performance than that. I'm just taking it one step at a time and see where it goes from there."

In Saturday's co-main event, former middleweight champ Ronaldo "Jacare" Souza made quick work of Derek Brunson, knocking him out in just 41 seconds.

Strikeforce CEO Scott Coker hinted in the days leading up to the fight that the winner could be in line to face middleweight champion Luke Rockhold.

"All my training partners talk about my hands," said Souza, a renowned Brazilian jiu-jitsu player. "I trained very hard for this fight. I'm very prepared for everyone, any time. I'm here for a fight. I'm the former middleweight champ, and I'll come back for more."

After the card, Coker said Souza likely will be next for Rockhold, who took the title from the Brazilian in September 2011.