SAN FRANCISCO — Sergio Romo raced down a tunnel inside AT&T Park on Saturday, slapping hands with a line of supporters chanting his last name during Fan Fest. He danced with some, posed for pictures with others and riled up the rest.

San Francisco’s new bearded closer has no trouble in the limelight.

After a dominant and demonstrative performance throughout October, Romo’s role for the defending World Series champion Giants will go beyond pitching the ninth inning this season. He’s one of the franchise’s faces now, especially with Brian Wilson and his bushy black beard likely gone, and he’s quickly learning about his newfound fame.

“I walk out to go warm up and it’s like, ‘Ahhh!’ I’m like, ‘Wow. I’m getting a big ol’ cheer?’” Romo said. “But then also just walking down the street and the reception that I get. I get recognized all the time now.”

From dancing behind teammates in the dugout on national television to wearing a T-shirt during the World Series parade that read “I Just Look Illegal,” Romo has never been afraid to show his personality. That’s maybe the biggest reason he’s such a hit in San Francisco, an ultra-progressive city where being different is cool.

The added popularity also comes with more pressure to perform on and off the mound.

Romo got a taste of the other side of the spotlight New Year’s Day, when a tiff with Transportation Security Administration agents at the Las Vegas airport drew a misdemeanor summons. Prosecutors have since dropped the charge, and Romo said he has put the incident behind him and is focusing on baseball again after a breakout October.

“Does it surprise me that I’m getting all the attention? No. But at the same time, you really can’t be prepared for it,” Romo said. “I think it’s just kind of like, there’s no, ‘Hey, man, how do I do this?’ Nobody sits there and explains things to you.”

Romo’s role this season will be the same one he left off doing in October.

He went 4-2 with 14 saves and a 1.79 ERA last year. Most came after Wilson, a rehabbing free agent the Giants don’t expect back, had elbow ligament-replacement surgery in April..

After Santiago Casilla struggled to close out games in Wilson’s absence, Romo and his whipping slider took over. In the playoffs, he had one win, four saves and a 0.84 ERA in 10 appearances.

Romo closed out three games in the World Series sweep against Detroit, including the final out when he struck out Triple Crown winner Miguel Cabrera looking on a surprise fastball. Romo said he went back and watched his postseason highlights this offseason to see for himself what he looked like on the mound.

“I still can’t believe it’s really happening, really,” Romo said. “It’s like, ‘Man, no way. No way, no how that’s me. But, oh, let’s play it again. Yup, it really is me. Rewind it. Yup, it really is me.’”

Teammates said the quality of Romo’s pitches has always been there — he just found a new level of confidence they hope will carry into the new season.

“I think if anything he proved something to himself. He didn’t have to prove anything to us. I always knew he had the stuff to do those things,” Giants lefty reliever Jeremy Affeldt, Romo’s throwing partner who received a new $18 million, three-year contract deal over the winter.

The Giants also rewarded Romo with a two-year contract earlier this week that can increase from $9 million to $10.2 million if he closes regularly.

Manager Bruce Bochy announced shortly after the season that Romo will be his closer going into 2013. He reaffirmed that decision on the eve of Fan Fest.

“I think he’s earned the right to be out there as we start the season,” Bochy said.

Bochy still promised to monitor Romo’s workload, which means the right-hander might not close every game early in the season. Romo, born and raised in the small California desert town of Brawley about 30 miles from the Mexican border, will play for his father’s native country of Mexico in the upcoming World Baseball Classic.

Romo’s durability as a closer is a concern. He has had elbow issues before and more than half of the time he throws that devastating slider, a pitch that requires a ton of torque and puts so much strain on the arm some teams discourage young hurlers from throwing it too often. The Giants also play so many close games, giving the closer more save opportunities.

Romo said he takes pride in being the ninth-inning man. He said he “was asked to be something a little bit bigger than something that I thought I could be, to play a little bit bigger role that I really thought that I could” last year and has the will and want to do it for a 162-game season.

But he still just calls himself “a reliever on the San Francisco Giants,” exemplifying the kind of chemistry and continuity the bullpen has built while winning two of the last three championships. The way Romo has handled his new role is also a big reason why No. 54 jerseys are soaring in popularity around San Francisco’s waterfront ballpark.

“It was definitely a different experience (from 2010),” Romo said. “I played a bigger role this time. I was asked to play a bigger role. I was very fortunate that I was able to deliver. Yeah, it was definitely different. I didn’t get a lot of time to sit down and relax a whole lot, but it was still just enjoying the ride. I kind of feel like I’ve been on a freight train ever since.”