(CNN) - A Democratic incumbent state senator conceded a tight race in Virginia Thursday, leaving the commonwealth's Senate evenly divided between Democrats and Republicans, with the Republican lieutenant governor breaking tie votes.
The result represents a big win for the GOP in Virginia, where Republicans control the three highest state offices, as well as the House of Delegates. Previously Democrats held a majority in the state Senate, which is now split 20-20.
Republicans will now hold an edge in the state Senate, since Republican Lieutenant Gov. Bill Bolling will break tied votes. Committee assignments and other procedural issues, however, will be negotiated between the parties.
State Sen. R. Edward "Edd" Houck conceded his race Thursday in a post on his Facebook page. His opponent, Republican Bryce Reeves, beat Houck by 223 votes.
"Today at 2:30 p.m. following a conference call with my legal team and campaign advisors, I determined that I must concede this election," Houck wrote. "I do so knowing that 'I have fought the good fight, I have finished the race, I have kept the faith.'"
Before the race was officially declared, the Republican governor of Virginia, Bob McDonnell, said Republican wins in the Virginia state Senate were significant.
Calling Republican wins in Virginia a "tremendous victory" during a conference call Wednesday, McDonnell said, "We are thrilled with the results of last night's election."
The president of the state Senate - a role served by the lieutenant governor - is responsible for casting the deciding vote in the event of a tie, the only time a lieutenant governor votes. Bolling was re-elected lieutenant governor in 2009.
McDonnell praised Bolling's ability to "determine matters" if needed, though a recount in the critical race is possible and cannot begin until election results are certified later this month.
–CNN's Rebecca Stewart contributed to this report.