Washington’s 3rd Congressional District is quickly becoming one of the most-watched races in the country as Democrat Marie Gluesenkamp Perez holds her lead against Republican Joe Kent.

In the district that pollsters thought was almost certain to go to Kent, a Gluesenkamp Perez win could become one of the biggest upsets this election.

After Friday’s ballot drop, the race is still tightening, now only separated by about 5,000 votes. On election night, Gluesenkamp Perez was up by about 11,100 votes.

There are likely more than 30,000 ballots left to be counted in the district, with most coming from Clark County, where Gluesenkamp Perez is leading by about 12 percentage points.

Voters across the country could start watching the race, as Democrats and Republicans are still fighting for control of the U.S. House of Representatives. Although it is still likely that Republicans take control, there are a number of too-close-to-call races across the country that could be the deciding factor.

In Washington’s 3rd Congressional District, Trump-endorsed Kent and small business owner Gluesenkamp Perez are facing off in a race that could become one of the biggest upsets in the country this midterm season. It could also determine how much support former President Donald Trump still has in Washington. A number of other extreme Trump-endorsed candidates across did not win this midterm election.

More ballots will be counted in counties in the district in the coming days. Clark and Thurston counties will update their results again on Saturday.