Incumbent Republican state Senator Win Stoller of Germantown Hills appears to have eked out a narrow lead against challenger Brett Nicklaus.
Stoller is leading Nicklaus by 528 votes in a tightly-contested race.
Stoller declared victory on Wednesday, but Nicklaus said he's not conceding defeat yet, citing the close margin and mail-in ballots yet to be counted.
"Our team continues to monitor results to ensure all legally cast ballots are counted," said Nicklaus in a Facebook post. "The democratic process demands full diligence. I acknowledge my opponent's apparent lead and look forward to final results."
Stoller was endorsed by GOP gubernatorial candidate and Senate colleague Darren Bailey. Nicklaus, a businessman from Dixon, was backed by House Minority Leader Jim Durkin and his allies.
Stoller donated to Travis Weaver's campaign in the 93rd District against state Rep. Mark Luft (R-Pekin).
Weaver is the son of former state Senator Chuck Weaver, who handpicked Stoller to replace him in the Senate.
