Getting an injunction isn't easy in the post-eBay v. Mercexchange era.

But getting one on a patent that the Patent Trial and Appeal Board has declared invalid—that is saying something.

A Quinn Emanuel Urquhart & Sullivan team led by partner Joseph Paunovich pulled off the feat last week for Santa Barbara, California-based startup Olaplex LLC in a hard-fought battle with beauty giant L'Oreal USA Inc. The dispute is over what Olaplex calls “the holy grail of hair product development”—its bond-building products that repair the breakage caused by bleaching.

U.S. District Judge Joseph Bataillon said last week that he will order three competing L'Oreal products off the shelves. He agreed with U.S. Magistrate Judge Sherry Fallon that the products likely infringe Olaplex's 9,498,419 patent. He also found that the patents will likely be found valid at trial, notwithstanding a PTAB decision last July to the contrary.

“Olaplex has made a strong case supporting validity at this point,” Battailon wrote. So long as the PTAB's decision remains on appeal, it “does not have preclusive effect as to this action unless and until the appeal is resolved,” he wrote.

The Federal Circuit is slated to hear the PTAB appeal this week. Olaplex has already had some success there: The appellate court ruled last year that now-retired U.S. District Judge Sue Robinson had construed Olaplex's patent too narrowly, and that Olaplex stood a good chance of winning an injunction under the proper construction. Now it has.

“It's been a long and hard-fought battle,” Quinn Emanuel partner Joseph Paunovich said Monday. “We're very happy to get this result.”

L'Oreal and Olaplex are the No. 1 and 2 players in the product space, Paunovich said. But it's a long way down, in terms of resources, from L'Oreal, which reported about $30 billion in sales last year, to Olaplex, which was formed in a Santa Barbara, California, garage and still numbers fewer than 30 employees.

L'Oreal is represented by Paul Hastings and Richards, Layton & Finger. They “heavily urged” Fallon to follow the PTAB's lead, Bataillon wrote in his order. L'Oreal told Fallon the PTAB decision and other developments had “unraveled” Olaplex's case.

“We're still a small startup company,” Olaplex Chief Legal Officer Tiffany Walden said Monday. “Getting this infringer off the market” will help Olaplex reclaim market share and grow its brand.