CHICAGO (CBS) — As House Democrats seek to maintain their control of chamber in November, two first-term representatives in Illinois will be key to that goal, and will face off against staunch conservative Republicans in the general election.

Congressman Sean Casten and Congresswoman Lauren Underwood were unopposed in Tuesday’s Democratic primaries, after both won traditionally Republican seats in 2018. Republicans will clearly make winning those seats back a priority in 2020.

Casten beat incumbent Peter Roskam two years ago in the 6th Congressional District, which had been represented by a Republican since 1973. Underwood defeated incumbent Randy Hultgren in the 14th District in 2018, taking away a seat that had been held by the GOP for all but three years since 1939.

Former Illinois State Rep. Jeanne Ives, of Wheaton, won the Republican primary on Tuesday, taking more than 70% of the GOP vote in the west suburban district, crushing Gordon “Jay” Kinzler.

A three-term state representative, Ives was one of the most conservative members of the Illinois General Assembly. Two years ago, Ives nearly defeated incumbent Gov. Bruce Rauner in the Republican primary.

Meantime, Illinois State Sen. Jim Oberweis, owner of Oberweis Dairy, held a narrow lead in a seven-way race in the 14th District, leading fellow Illinois State Sen. Sue Rezin 25.1% to 22.8% with 87% of precincts reporting. Catalina Lauf, a consultant and one-time Trump appointee to the U.S. Department of Commerce, was close behind at 20.6%.

“This has been a spirited and well fought campaign. I have been disappointed in the negative tone that the campaign has taken, but all of that is behind us. Now is the time for us as Republicans to come together and finish the mission which is to defeat Lauren Underwood in November,” Oberweis said in a statement late Tuesday night.

Oberweis has been a state senator since 2013, and has mounted failed bids for the U.S. Senate in 2002, 2004, and 2014; for governor in 2006, and for Congress in 2008.

In other congressional races, incumbent Democrats Bobby Rush, Robin Kelly, Mike Quigley, Danny Davis, Raja Krishnamoorthi, and Bill Foster handily won their primaries. Congressmen Jesus “Chuy” Garcia and Brad Schneider, and Congresswomen Jan Schakowsky and Cheri Bustos were unopposed in their Democratic primaries.

Republican incumbents Mike Bost, Rodney Davis, Adam Kinzkinger, and Darin LaHood also were unopposed in their respective primaries.

In a likely upset, progressive challenger Marie Newman is leading eight-term incumbent Dan Lipinski in the Democratic race in the 3rd District. If she holds her lead, she will face Will County board member Mike Fricilone in the general election.

The only open congressional seat in Illinois, the 15th District, will see Democrat Erika Weaver face off against Republican Mary Miller in November.