Campaigners have won a High Court injunction stopping Surrey County Council from replacing paid staff at 10 libraries with volunteers.
The council has been told not to take any irrevocable steps to implement the plan until further order of the court.
Surrey Libraries Action Movement (Slam), which issued proceedings on Tuesday, said it was surprised the injunction was granted so quickly.
Surrey said it was disappointed at the court's decision, issued on Friday.
The Conservative-run council wants volunteers to run 10 libraries in Bagshot, Bramley, Byfleet, Ewell Court, Lingfield, New Haw, Stoneleigh, Tattenhams, Virginia Water and Warlingham.
It has already dropped plans to hand over another nine libraries to volunteers.
Slam spokesman Lee Godfrey said the library service in the affected communities would be severely diminished by the proposed changes.
"We were expecting a three-week wait while the judge considered the merits of the case before deciding whether to issue an injunction," he said.
"It didn't take the judge very long to decide that our case was strong enough to merit a quick injunction.
"We are very pleased about that."
He said the council now had two weeks to serve its evidence to the High Court, which would then decide whether the case should go to a judicial review.
The council said in a statement: "We are disappointed at the court's decision.
"We understand that people care for libraries and that's why we are working with local communities to keep all 52 Surrey libraries open."