SCOTTSDALE, Ariz. -- At his Scottsdale Stadium dressing stall, Santiago Casilla displayed a glittering gold medal for participating on the Dominican Republic team that won the World Baseball Classic.

But Casilla's most enduring prize will be the fulfillment residing within his soul.

Casilla knows all about success, having played on the Giants teams that captured the World Series in 2010 and 2012. The right-hander wouldn't say whether helping his country win a title was sweeter than helping the Giants triumph, but he acknowledged that he derived a special feeling from pitching in the Classic.

"It's something a little different," Casilla said Thursday upon rejoining the Giants. "The emotion's unbelievable when you're playing for your country. Everybody's watching the game in the Dominican."

They saw Casilla and his fellow relievers excel. The Dominican Republic finished the tournament 8-0, owing largely to its bullpen. Casilla, Pedro Strop and closer Fernando Rodney led a relief corps that finished the Classic with 25 2/3 consecutive scoreless innings. Casilla contributed five scoreless innings spanning five appearances. He yielded just one hit -- a triple to Giants teammate Angel Pagan, who played for Puerto Rico. Casilla also walked Pagan in another confrontation.

"I said, 'Hey, only fastballs for you,'" Casilla jokingly said of his faceoffs with Pagan.

That didn't necessarily differ from the D.R.'s approach to relief pitching. Casilla, who routinely reaches 95 mph with his fastball, found himself in a bullpen where he actually wasn't one of the hardest throwers. "Everybody throws 97-98. Unbelievable," Casilla said.

The postgame celebration was apparently just as unreal. "Nobody slept," said Casilla, 32. "Everybody was happy."

With the return of Casilla and Pagan, who visited the clubhouse briefly and will start Friday in center field, the core of the Giants' projected Opening Day roster is whole again. Though manager Bruce Bochy will continue to regulate the activity of his regulars, he'll begin to assemble them in the same lineup to reacquaint them with each other.

"We're getting close," Bochy said, referring to the April 1 opener at Dodger Stadium. "It's a good time to have all the guys back and playing together."

That particularly includes the bullpen, which has been depleted for much of Spring Training. Casilla, Sergio Romo (Mexico) and Jeremy Affeldt (United States) participated in the Classic, while left-handers Javier Lopez and Jose Mijares dealt with injuries.

Bochy's not worried about overexposing any of his top relievers. He said Casilla, Affeldt and Lopez are more than just specialists and remain capable of working a complete inning or longer.

Casilla, who signed a three-year, $15 million contract during the offseason, likely will be asked to handle multiple responsibilities, including the closer's role that he occupied part time last year. Casilla, who saved a team-high 25 games for the Giants in 2012, probably will be asked to preserve leads when Romo, the current relief ace, needs a break.

Thriving in the Classic, which was an intense event for Casilla and his countrymen, should prepare him for the rigors of the coming season.

"Any kind of playoff experience makes you better and more confident," Bochy said. "Part of being a great player is performing under pressure. It should help his confidence."