Sen. Jon Tester (D-Mont.) won reelection Wednesday morning, surviving a tight race with Rep. Denny Rehberg (R) that stretched into the day after voters went to the polls.

With 85 percent of precincts reporting, Tester led Rehberg 49 percent to 45 percent. The Associated Press has called the race for Tester.

Tester's win is more good news for Senate Democrats, who kept their majority, picking up seats in Massachusetts and Indiana, while the GOP picked up Nebraska. Democrat Heidi Heitkamp appeared headed for victory Wednesday morning in North Dakota. A win would be a surprise hold there for Democrats.

Tester and Rehberg polled neck-and-neck throughout the race, with the senator banking on his centrist appeal and farmer image in a red state and Rehberg attempting to tie Tester to the national Democratic party and President Obama.

Tester was first elected to the Senate in 2006, defeating embattled Sen. Conrad Burns (R) and, in the process, returning Democrats to the majority.

Republicans had banked on a Rehberg win helping them return to the majority -- something that now appears to be out of reach.

Rehberg is a six-term member of Congress, former lieutenant governor and rancher. This is his second failed Senate campaign. He lost to Sen. Max Baucus (D-Mont.) by five points in 1996.