The Carter administration and organized labor lost what was seen as a crucial vote to break the four-week Senate filibuster against their labor law revision package yesterday but will try again today.

Labor lobbyists conceded privately that 58-to-41 vote to cut off debate - two votes short of the 60 necessary to invoke cloture - was a setback in their game plan to break through yesterday on the fourth cloture attempt.

They expressed nervous optimism that they will get 60 or more votes today, and Sen. Orrin G. Hatch (R-Utah), leader of the filibuster forces, spoke cautiously, too.

"I think that (58 votes) was their high-water mark," he said, but added, "If we lost tomorrow I'll be very upset. . . all I can say is that we're going to hang in there."

Labor Secretary Ray Marshall, who made an unusual appearance in the Senate gallery to watch the vote, apparently in anticipation of victory, said he had "some reason to hope," that cloture will be invoked today.

He said the administration may have to make more concessions to get the last two votes, but cautioned that it is nearing its limit on concessions.

Although they failed to reach their self-imposed goal of 60 votes yesterday, proponents of the bill - which would generally make it easier for workers to unionize and win contracts - picked up four senators, all Republicans, from Tuesday's 54-to-43 cloture vote.

The four were Sens. John H. Heinz, III, of Pennsylvania, Charles H. Percy of Illinois and Ted Stevens of Alaska, all of whom had previously supported the filibuster, and Sen. Lowell P. Weicker of Connecticut, who was absent Tuesday but previously voted to end the debate.

Sources said that administration and labor forces are now looking to pick up at least one vote from among these Democratic senators: Russell B. Long of Louisiana, Edward Zorinsky of Nebraska, Lawton Chiles of Florida, Howard W. Cannon of Nevada and Dale Bumpers of Arkansas.

It is understood that Sen. John Sparkman (D-Ala.), will vote for cloture if his vote is needed to make 60. He voted no yesterday.

Organized labor's search for a 60th vote yesterday focused on Zorinsky and Bumpers, but there were indications last night that attention has shifted to Long.

The key question is how long the Senate Democratic leadership will allow the filibuster to tie up the Senate.Nearly 1,000 amendments await action once debate has ended.

Some sources indicated a major reappraisal may occur next week if the filibuster isn't broken by then, although union lobbyists say Senate Majority Leader Robert C. Byrd (D-W.Va.) has assured them he will keep the bill on the floor as long as it takes.

The bill, which has provoked massive opposition from business groups, would set deadlines for union representation elections and impose stiff penalties for employers who violate existing labor law in thwarting union organizing and bargaining drives. A stronger version of the bill passed the House last year.