Uvaldo Acosta will cock his arm way back when approaching the net for a spike, as the opponents crowd the net on the other side for the block. Instead of going for the kill, however, he'll tap the ball lightly for the point, grin at the canny play and smoothly slap every one of his teammates' hands while running around the volleyball court.

"I'm always a happy person," said Acosta, a freshman outside hitter for George Mason's seventh-ranked volleyball team, before last night's Patriot Center match with second-ranked UCLA. "I've never had anything to be embarrassed of. In my family, we're always laughing."

George Mason, which had a 7-0 record before losing to Southern California Friday night, lost again, 15-10, 15-11, 9-15, 15-8, to UCLA on the second night of East vs. West doubleheaders on the Fairfax campus. USC defeated Ball State, 15-5, 15-2, 10-15, 15-9, in the evening's first game.

Those defeats notwithstanding, as he develops at George Mason, Acosta is bringing enthusiasm and skill to a team aiming at the national championship after third places the last two years in the NCAA playoffs.

"He's the world of difference," said junior setter Dale Witmer. "He's exactly what we needed. He can adjust to any setup. He can make the setter look good.

"He's got a dynamic personality. He never gets depressed, is never one to pout."

At 5 feet 11 inches, Acosta is dwarfed by teammates Hokan Bjorne (6-7), Moyo Kasim (6-6) and Mike Schwob (6-7). Yet, Acosta is perhaps the most skillful on the Patriots team.

Acosta, whose high school in El Paso, Tex., did not have a boys volleyball program, gained most of his experience playing on the U.S. Junior National Team last summer. In a tournament in Finland, he was named most valuable player.

The award was quite an accomplishment for Acosta, considering that his freshman year of high school, when his peers on the West Coast and other fertile volleyball areas were involved in competition, he was practicing in the back yard of his home.

"I played in the back yard by myself," said Acosta. "I'd bump the ball to myself and set a lot. My sister would come out and put up a net and we'd play.

"I had to learn from my sister Carmen and read a lot. I probably read the same book 100 times."

Acosta, who said he played football, baseball and was all-state in basketball in high school, tried out but was cut from the U.S. Sports Festival team his junior year. The following year he made it and last summer he developed his game with the Junior National team.

"With the Junior National team I learned a lot," said Acosta. "I never had any coaching. From there, my whole game just changed.

"I learned positions to hit, different types of sets. I learned to pass a little bit lower."

"He's a smart hitter," said Witmer. "He knows where to hit and how hard."

It was also with the national team that he met Patriots Coach Ron Shayka, who was an assistant. Before he ran into Shayka, he said he had intentions of going to Southern California, which is presently ranked No. 3 in the nation, beat George Mason in a tight five sets Friday night in the East vs. West meet, and is a traditional power.

Before he met Shayka, "I wasn't even thinking about coming to Mason," said Acosta. "The coach didn't beg me to come, he was real calm. I just decided a week before school started to come.

Then he said, "If I tell you the truth (about coming to Mason), I would probably die."

But he added, "I was tired of the West winning so much. I said, 'I'll take it. I want the East to win.' "