Schaumburg has won six games in a row to equal a franchise record set earlier this season.
Phelan (4-1) allowed just 2 hits. Following a two-out single in the third, the Frontier League all-star retired 16 in a row before the leadoff man reached in the ninth and eventually scored the lone run.
The Boomers provided Phelan with plenty of support in the third inning, sending 10 men to the plate and scoring 4 runs.
Schaumburg took advantage of wildness from Joliet starter Corey Kimes, drawing 4 walks in the inning. Michael Valadez drew a bases-loaded walk to force home the first run and Jordan Dean added a 2-run single.
Schaumburg added 4 more in the fifth and the rout was on.
Dean finished with 4 RBI and four players posted 2 hits.
The Boomers (38-28) return home today for a three-game series with Rockford.