Rachel Ventura won the Democratic primary for the 43rd state Senate District seat, while the Republican candidates were locked in a tight race late Tuesday night.

Unofficial results as of late Tuesday indicated Ventura led Eric Mattson in the Democratic primary 7,179 to 5,325 with 99.7% of votes counted in DuPage County, and all precincts reporting in Will County.

The race among the Republican candidates was much closer, as Diane Harris led Michelle Lee 4,915 votes to 4,797. The vote total does not include mail-in and provisional ballots.

The 43rd state Senate District encompasses portions of DuPage and Will counties and includes Woodridge, Naperville, Bolingbrook, Romeoville and other nearby communities.

Ventura, a Joliet resident and Will County board member, overcame what she believed to be Mattson’s unfair advantage when he was appointed to fill the 43rd state Senate seat after John Connor stepped down in May to care for a family member.

Harris, a Joliet Public Library trustee, was raised in a Democratic-leaning household but said she’s been a Republican for more than 40 years. Lee, elected to the Joliet Junior College Board of Trustees, said she shifted to the Republican Party after being disappointed in the Barack Obama presidency.