Nevada Democrat Jacky Rosen is in a neck-and-neck battle in her bid to return to the U.S. Senate for a second term, while her party lost its slim voting majority in the upper chamber of Congress.

Democratic Sen. Jacky Rosen trailed Republican Sam Brown by less than 1,000 votes as Nevada counties stopped reporting results early Wednesday morning. As of Wednesday at 3 a.m., Brown led Rosen by 870 votes — or 0.

This would be considered a major upset. Polls and election forecasts had Jacky Rosen leading Sam Brown strongly throughout the entire campaign.