Collins is a former McDonald's All-American.
The Wolverines racked up 13 runs on 11 hits.
After taking the first game Saturday, Maryland struggled on the mound in game two.
The Terps combined for 36 hits between both games.
She averaged 1.5 points and 8.9 minutes per game during her three years with the Terps.
Coach Rob Vaughn was ejected for protesting the Wildcats' go-ahead run in the eighth.
With the help of sloppy Illini defense, the Terps posted four ninth-inning runs.
Charles averaged 17.0 points and 6.7 rebounds during her junior season.
After going 26-3 in the regular season, the Terps lost in the Big Ten title game and the NCAA tournament Round of 32.
The Terps hadn't surrendered more than 25 offensive rebounds in over a decade.