CHICAGO – Illinois Republicans emerged Wednesday from a combative primary in which a freshman congressman ousted a 20-year veteran and pledged to aggressively defend the party’s recent gains, despite a new congressional map that whittles the state into districts favoring Democrats.

While GOP leaders expressed confidence they could hold onto most of the seats they won in 2010 during a tea party-backed surge, Democrats eyed Illinois as a prime opportunity to inch closer to control of the U.S. House.

“Illinois is going to be absolutely pivotal to what happens in November,” said New York Rep. Steve Israel, chairman of the Democratic Congressional Campaign Committee.