Nathan Main's single in the bottom of the sixth secures an 11-10 victory over Suffield on Sunday.
Team continues its run with 12-0 victory on Saturday.
The 11/12 All-Stars defeat Windsor 5-3 after trailing by three runs.
The team has won 14 out of its first 16 games of the year.
Nathan Main's walk-off single in the bottom of the sixth capped a comeback for the Nationals, who improved to 3-0 in District 8 pool play.
South Windsor opens District 8 group play with a 7-5 victory over Thompsonville.
Pitcher Brian Finnegan yields just two hits over seven innings to power South Windsor to a 3-1 victory.
After a tough loss in the state Class LL tournament, many of the South Windsor High School players struggled with the transition into the American Legion season.
Americans and Nationals begin District 8 pool play for 11-12 year olds on July 2.