CHICAGO (CBS) — Tammy Duckworth has defeated incumbent Republican Mark Kirk in the Illinois U.S. Senate race.

“This was a truly grass roots effort,” Duckworth said. “Victory would not have been possible without each and every one of you.”

The contest is among about a half-dozen Senate races closely watched nationally as the Republicans try to hold onto their majority.

“We need four new Democratic senators,” Illinois Sen. Dick Durbin told CBS 2’s Derrick Blakley. The country “is looking to Illinois for one of them.”

Duckworth enjoyed overwhelming support among non-whites (85 percent) and women (62 percent), according to CBS 2/Edison Research exit polling data. Kirk’s support came from white men (57 percent).

Duckworth, a two-time congresswoman representing the northwest suburbs, is a decorated Iraq War veteran.

Duckworth lost her legs when her helicopter was shot down in 2004.

Kirk’s scathing disavowal of GOP presidential nominee Donald Trump likely won him votes in the Chicago area but cost him downstate.

“To my friends and staff, you mean the world to me,” Kirk told his supporters after calling Duckworth to congratulate her on her victory.

Kirk invited Duckworth to the Billy Goat Tavern for a beer. “This beer summit with show kids across Illinois that opponents can peacfully bury the hatchet.”

Kirk also suffered from a series of missteps, including more recently, mocking Duckworth’s immigrant background and her claim that her family’s military service dates back to the Revolution.

During a debate with Kirk, Duckworth said her family has “served this nation in uniform going back to the Revolution.”

Kirk responded that he had forgotten that the congresswoman’s “parents came all the way from Thailand to serve George Washington.”

Kirk apologized for the comments.

Kirk, who suffered a stroke in 2012 and returned to work one year later, had been criticized before for off-color statements.