Phillips, a left-hander in the Chicago White Sox organization, allowed one run on three hits en route to his second victory of the tournament. He is 2-0 with a 1.38 ERA in two outings in Cuba.
The 24-year-old could be in line to take the mound in Team USA's final game of the tournament against the host country on Tuesday.
The United States belted three more home runs, increasing its total to 13 in six games.
The game was scoreless into the third inning, when Michael Bourn and Skip Schumaker drew back-to-back walks. Bobby Hill advanced both runners with a sacrifice, setting the stage for Mike Kinkade's two-run single to right.
After the Dominican Republic halved its deficit in the fifth on a sacrifice fly, Mark Reynolds -- who replaced the injured Chad Allen earlier in the game -- restored the Americans' lead with his fourth home run of the tournament.
Team USA tacked on four runs after a misplayed double-play ball off Bourn's bat extended the inning. Skip Schumaker took advantage as he launched a grand slam off reliever Alberto Gonzalez to make it 7-1.
Team USA plated five more runs in the eighth on Hill's RBI triple, a run-scoring single by Kinkade and Bryan LaHair's two-run blast. Billy Butler's RBI single ended the game because of the mercy rule governing international competition.
Schumaker went 2-for-4 with three runs scored and is batting .440 with a team-high 14 runs scored. Butler, Reynolds and Kinkade each contributed two hits.
Allen left in the second inning following a collision at the plate as he tried to score on a single. The nature and severity of the injury was not disclosed.
Team USA continues second-round play on Saturday against Nicaragua at Nelson Fernandez Stadium.
NOTES: The game was delayed at the start by one hour due to a passing thunderstorm. ... Team USA held an optional workout on its off day Thursday. ... The remainder of the day was spent touring Old Havana. ... There may be no further night games at Nelson Fernandez Stadium due to insufficient lighting. On Wednesday, after the U.S. loss to Venezuela, two lights exploded as glass shattered and fell into the stands. No one was injured. ... After the national anthems, Team USA shook hands with the Dominican players as a gesture of goodwill and sportsmanship. ... Team USA has outscored its opponents, 61-29. ... The Americans have recorded at least 10 hits in four of six games. ... Reynolds leads the team with four homers and is tied for second with seven runs scored, despite playing in only four games.