Los Angeles improved to 5-0 with its semifinal win Saturday, and will meet the Dominican Republic in the final Sunday. (RBI Baseball)

BLOOMINGTON, Minn. -- Los Angeles baseball coach Shannon Williams has spent 15 years coaching in the Reviving Baseball in Inner Cities (RBI) program.

Williams, Los Angeles' junior RBI coach this year, has won four RBI World Series titles as a coach.

So when he said that Saturday's semifinal victory was the most exciting game he's been a part of, it's saying something. Williams has seen a lot of good games in the RBI World Series.

"By far this is the most exciting game I've ever had," Williams said. "In a semifinal game, to come up clutch like that with the way these guys that have been battling all summer, by far this is the most thrilling victory I've had."

It might be the most thrilling game of the 2011 RBI World Series, no matter what happens in Sunday's championship games. Los Angeles came from behind and beat the Chicago White Sox, 5-4, in 11 innings on a walk-off double to the left-field wall.

Los Angeles (5-0) will face the Dominican Republic (4-1) in Sunday's junior division championship at Target Field. The Dominican Republic beat Philadelphia, 14-3, in the other junior final.

Venice, Calif., beat the Chicago Cubs, 5-3, to advance to the senior division championship. Venice (3-1-1) will play Harrisburg, Pa., (3-1-1), which beat Venezuela, 6-5.

Los Angeles and the Dominican Republic will play in the first game on Saturday at 10:30 a.m. ET. Venice and Harrisburg are scheduled to play at 2 p.m. ET. The games will be broadcast live on the MLB Network and will stream on MLB.com.

Viewers can only hope to see a game as competitive as the one that Los Angeles and Chicago put together in Saturday's junior semifinal.

Chicago opened the scoring with three runs in the first inning and another in the second, but Los Angeles recovered to tie the score at 4 in the fourth.

But coming from behind was nothing new to Los Angeles, as it has trailed early in its last four games.

"It takes these guys a while to get going," Williams said. "These guys respond to pressure well. It kind of gives the parents and coaches more gray hair, but the kids are just having fun."

Both teams had their chances to take a lead, but it remained 4-4 until the extra innings. Los Angeles thought it was going to score the winning run in the 10th, but Chicago's James Davidson threw a runner out at home plate for the first out as Chicago escaped the threat.

In the 11th, Los Angeles had another baserunner reach, and Williams sent in Tyree Davis to pinch-run. Davis, the team's usual starting center fielder had hurt his wrist and was unable to start the game because he couldn't swing the bat.

But his legs were healthy. Davis was one of the fastest players in the junior division at Wednesday's workout session. Chicago's pitcher tried to pick Davis off of first base, but the throw got by the first baseman and Davis made it all the way to third with nobody out.

"It's all a byproduct of his speed," Williams said. "They know he is fast and they kept throwing over there, and they threw one away. No one else on this team can go first to third there.

"He played his part. We used his legs to win. It's a team effort, a collaborative effort."

Los Angeles catcher Aaron Vilaubi, who had caught 30 innings over the past two days, stepped up and hit a long fly ball over the left fielder's head to score Davis and put Los Angeles in the championship game.

"It was an awesome display by both teams," Williams said. "We were the home team and I think whoever had the last at-bat was going to win, and we had it today. I think if the White Sox had the last at-bat, they would have won."

While Chicago didn't reach the title game, it can take solace in knowing that it might have played the most memorable game of the tournament.

"My heart was racing 100 miles-an-hour for the whole game," Chicago coach Kevin Coe said. "It was absolutely incredible. The kids are heartbroken. We had our opportunities and they had their opportunities.

"We're an aggressive baseball team. There were certain situations later on in the game where we lost our aggressiveness, and I think it kind of hurt us."

The Dominicans reached the junior division championship with a hitting display against Philadelphia, including a home run from Juan Arias that cleared the center-field fence.

"He's a natural power hitter," Dominican coach Christian Pimentel said through interpreter Marcos Medina.

As the defending champions, the Dominicans feel good about heading to the championship game. Pimentel has said that this year's team is different from last year's, but possibly even better.

"The difference is that the other team had participated before," Pimentel said. "With this team, there's only two or three that participated before. With this team, I see the desire and the will to bring the championship home."

Los Angeles opened the playoffs with a 6-2 win over Detroit, and the Chicago White Sox beat Atlanta, 5-0.

The Dominicans held on for a 3-1 win against Jersey City and Philadelphia upended Houston, 5-4.

The senior playoffs opened with the Chicago Cubs upsetting top-seeded Tampa, 6-0. Venezuela also topped Houston, 4-2, in the first round.

Harrisburg reached the semifinals with an 8-4 win over defending champion Houston. Venice beat Jersey City in the first round, 9-8.