Senate Republicans are getting what's expected to be a short-lived win in a fight over unemployment benefits in Democrats' nearly $1.9 trillion coronavirus bill.

Sen. Joe Manchin (D-W.Va.) voted with all 49 Republican senators — Sen. Dan Sullivan (Alaska) is absent due to a family emergency — in support of a proposal from Sen. Rob Portman (R-Ohio) to provide a $300 per week unemployment payment through mid-July.

But Democrats are expected to strip out Portman's amendment and replace it with a deal they announced on Friday night, after a nearly 12-hour delay, before they pass the coronavirus deal likely on Saturday.

Democrats are still waiting for a Joint Committee on Taxation score about the cost of the Democratic proposal, which would provide a $300 per week payment through Sept. 6.

"We expect Senator Portman to offer his UI amendment and for it to pass. However, it will be superseded by Senate Democrats’ new UI agreement, which will be offered and passed as an amendment tonight," a Democratic aide said about the path forward.

Though Manchin supported Portman's amendment, he's also expected to support the Democratic deal. In addition to the weekly payment, the Democratic amendment will let the first $10,200 in unemployment benefits be tax free for households with incomes of up to $150,000.

"We have reached a compromise that enables the economy to rebound quickly while also protecting those receiving unemployment benefits from being hit with [an] unexpected tax bill next year," Manchin said in a statement endorsing the Democratic deal.

Democrats effectively put the debate on the coronavirus bill on hold for nearly 12 hours Friday as they tried to craft an agreement on the unemployment payments that could win over the entire caucus.

Democrats had initially said on Friday morning that they had a deal to provide a $300 per week payment until early October.

But as they day dragged on it became clear that they were still trying to wrangle together the caucus.

Majority Leader Charles Schumer (D-N.Y.) argued once the Senate moved forward just before 11 p.m. that Democrats were united.

"The agreement that’s been reached will allow us to move forward with the American Rescue Plan," he said. "Senate Democrats are completely united in our belief about how important this entire bill is for our fellow Americans."