Santos pummels Carano with such ferocity that the bout is called off with one second remaining in the first round, with a then-network-record 576,000 homes tuning in, a mark the bout would own for nearly two years.
After absorbing the beating, Carano, whose stardom was propelled by equal parts skill, charisma, and favorable matchmaking, never returned to the cage, opting instead for a Hollywood career. In her absence, women's MMA soon took on the distinct feeling of a novelty that had passed its peak.
Fast forward three years to last weekend, though, and women's fighting is in its biggest spotlight since the Carano-Santos blockbuster.
Strikeforce bantamweight champion Ronda Rousey has broken through in a way like no fighter since Carano. But unlike Carano, who had an undeniable All-America charm, Rousey is a brash, trash-talking rock star -- right down to her ring entrance music choice of Joan Jett and the Blackhearts' Bad Reputation -- with world-class athletic credentials to back up her smack talk.
The 2008 Olympic judo bronze medalist from Southern California has laid waste to everyone in her path, cleaning out the competition at 135 pounds. Saturday night in San Diego, Rousey claimed her latest victim, former champion Sarah Kaufman, tearing through in just 54 seconds a fighter who entered the bout with a 15-1 record.
It would be a stretch to say that Rousey has become a star fighter in the class of Anderson Silva or Jon Jones. But there are enough encouraging signs to point to the notion that, three years after women's MMA was presumed to have reached its zenith, the sport has staying power after all.
Tuesday, Showtime released its television ratings. While Rousey has a way to go at the box office, she's picking up steam as a ratings draw. Saturday night's Strikeforce event, with Rousey as the headliner, drew an average of 529,000 viewers, the largest MMA rating of 2012 on the premium cable network. The viewership jump over Rousey's previous fight, on March 3 against Meisha Tate, was 23 percent.
The broadcast peaked with 676,000 viewers for Rousey's win over Kaufman; Showtime also claimed that its male 18-49 demographics was its best since the February 2011 bout between Fedor Emelianenko and Antonio Silva, which is the most watched MMA fight in the network's history.
Three years after Carano's peak, can women's MMA sustain the momentum? That will depend on three factors: Finding Rousey a viable rival, building roster depth and proper promotion.
Rousey has won all six of her fights via first-round armbar. While this has helped draw attention, one-sided beatdowns will only carry her so far. To develop legitimate staying power, she'll need to be placed in a fight with someone the public perceives will have a fighting chance in the cage.
That someone is Santos, who has dominated her opposition at 145 pounds since defeating Carano in 2009. But she's also under suspension for steroids after testing hot last December. If and when "Cyborg" is cleared to return, a women's super fight between Strikeforce's two most dominant fighters has the makings to surpass Carano-Santos in viewer interest.
"The Carano-'Cyborg' fight was one of the highest-rated shows on Showtime, was the highest-rated MMA show on Showtime until we started the heavyweight tournament in February of last year," Strikeforce founder Scott Coker said Saturday. "For two years it held the record. So I believe once we get [Rousey-Santos] together, it will beat the past ratings record and the past gate record because it's going to be probably the biggest fight in the history of [women's] mixed martial arts."
Rousey and Santos have already begun to posture over the logistics of a potential fight. Rousey insists Santos has to come down to 135 pounds and meet her; Santos says she's incapable of getting that low. Ultimately there's too much at stake for the pair not to meet somewhere in the middle.
While Rousey and Santos appear laps ahead of their competition, there's undeniably a pack of women's fighters engaging in quality bouts who simply weren't around to provide depth three years ago. Twice in the past month alone, women have engaged in bouts likely to make the final list of contenders for Fight of the Year.
On July 28, the all-women's Invicta Fighting Championship featured a main event in Kansas City between 2004 Olympic women's wrestling silver medalist Sara McMann and veteran Shayna Baszler. McMann, a star in the making, outlasted Baszler in a 15-minute battle that featured a little bit of everything.
Saturday, on the same card as Rousey-Kaufman, another women's fight stole the show. Tate met grizzled veteran Julie Kedzie in Tate's first bout since losing to Rousey. The result was a three-round battle filled with dramatic twists and turns. Kedzie appeared to have the bout finished when she dropped Tate with a ferocious head kick midway through the final round, but Tate kept her wits and finished Kedzie with an armbar about 90 seconds before she likely would have lost a decision.
McMann, Baszler, Tate and Kedzie are just some of the names in a talent pool that includes the likes of talented striker Germaine de Randamie, former Marine and openly gay fighter Liz Carmouche, and lighter-weight standouts like strawweights Jessica Aguilar and Megumi Fujii and atomweight Naho Sugiyama.
The bad news, at least in the short term? The only fans who saw McMann-Baszler were diehards who followed a live online stream and those who later watched on YouTube when word of mouth about the bout spread; and Tate-Kedzie was bizarrely relegated to Saturday's undercard, which was telecast on the lesser-watched Showtime Extreme.
UFC president Dana White has adamantly opposed the addition of women's divisions to MMA's biggest stage over the years. His frequently stated reason is there aren't enough quality fighters to fill out the various divisions.
When the UFC's parent company, Zuffa LLC, purchased Strikeforce in 2011, White took a laissez-faire approach to its women's division, neither getting in its way nor particularly going out of his way to promote it.
But MMA's grand poobah seems to be coming around. He showed up in San Diego on Saturday and not only praised Rousey, but also tweeted his excitement over Tate-Kedzie throughout the fight. On Tuesday, he told a Las Vegas radio station that he could envision a potential Rousey-Santos fight headlining or co-headlining a major UFC event. Then Tuesday night during a Facebook chat with UFC fans, White said he's "warming up" to the idea of women's fighting.
Can White, with his vaunted promotional acumen, be fully sold on the viability of women's fighting? The answer to that question will ultimately decide whether women's MMA has staying power this time around or whether this summer's excitement turns into 2009, Part II.