One of Uber’s top engineers will no longer be able to work on a key self-driving car technology, a U.S. judge ordered, adding a new hurdle in the ride-hailing company’s race to get to market.

Uber will be able to continue working on its self-driving car technology, the U.S. judge said, but embattled engineer Anthony Levandowski must be removed from any work relating to a key technology called LIDAR.

Alphabet’s self-driving car unit, Waymo, has sued Uber, claiming that the ride-hailing start-up is using key parts of Waymo’sself-driving technology. The fight centers around Levandowski, who was deeply involved in Google’s self-driving car initiative before leaving to found a start-up, Otto, which Uber later acquired.

The injunction on Levandowski’s work is part of an order that was revealed last week in sealed documents. That order also denied Uber’s argument to move the fiery lawsuit to private arbitration, and referred the case to the U.S attorney general. The result of the order “tips sharply in Waymo’s favor,” California judge William Alsup wrote, although some of Waymo’s requests were also denied.

“Competition should be fueled by innovation in the labs and on the roads, not through unlawful actions. We welcome the order to prohibit Uber’s use of stolen documents containing trade secrets developed by Waymo through years of research, and to formally bar Mr. Levandowski from working on the technology,” a Waymo spokesperson told CNBC. “The court has also granted Waymo expedited discovery and we will use this to further protect our work and hold Uber fully responsible for its misconduct.”

Waymo’s lawyers have asserted that Levandowski stole documents from Alphabet, and that Levandowski was already negotiating with Uber before he left Alphabet.

Levandowski has already said he would recuse himself from work related to the disputed technology. But an Uber engineer recently testified that Levandowski communicates with the new self-driving boss on a day-to-day basis.

The case comes at a time when the self-driving car business is fiercely competitive — and any setback could impact companies’ abilities to test their cars on the road and beat rivals to market. Uber has called the case a “baseless attempt to slow down a competitor.”

While Levandowski will no longer be able to work on one of the most important sensors for self-driving cars, an Uber spokesperson told CNBC that they are pleased they can continue on their overall technology.

“We are pleased with the court’s ruling that Uber can continue building and utilizing all of its self-driving technology, including our innovation around LiDAR,” an Uber spokesperson told CNBC on Monday. “We look forward to moving toward trial and continuing to demonstrate that our technology has been built independently from the ground up.”