Coming off a last-minute surge, state Sen. Deb Fischer won the GOP nomination for U.S. Senate tonight, according to the Associated Press.

Up until about two weeks ago, Fischer was largely written off as a candidate. For most of the cycle, state Attorney General Jon Bruning was the undisputed GOP frontrunner. He came in second place.

Bruning had a deep organization, but Fischer’s momentum proved too strong.

The favorite among anti-establishment conservative groups, state Treasurer Don Stenberg came in third place. In recent days, state and national Republicans began to describe the Stenberg effort as a miscalculation on the part of Sen. Jim DeMint (R-S.C.) and others.

The Club for Growth, which had supported Stenberg, moved within seconds of the Associated Press story to congratulate Fischer.

“While we did not support Deb Fischer, we are encouraged by the strong pro-growth stands she took in this campaign, and we expect she will live up to those commitments in the Senate next year,” the club’s president, Chris Chocola, said in a statement.

The club is widely credited with mortally wounding Bruning with negative advertising, which gave Fischer a path to victory.

As for the Democrats, one national strategist insists Fischer’s surprise nomination does not improve GOP chances to pick up this seat. The source says she is unvetted. He also added that because her campaign was so scrappy until so late, national Republicans will need to pour resources into the race to keep pace with Democratic nominee, former Sen. Bob Kerrey.

Looking ahead, this race is central to both parties’ strategies for Senate control. It is a top opportunity for a Republican pickup in the fall, but Democrats managed to pull out a top recruit in Kerrey.

Roll Call rates this race as Leans Republican.