The federal judge who will decide whether lawyers at Quinn Emanuel Urquhart & Sullivan get to pursue an antitrust case against former client Uber Technologies Inc. greeted a lawyer from the firm with extreme skepticism and a flurry of difficult questions Friday.

U.S. Chief Magistrate Judge Joseph Spero of the Northern District of California opened a hearing on Uber's motion to disqualify the Quinn Emanuel lawyers by raising concerns about the similarities between the lawsuit he's overseeing and an earlier suit where Quinn played the defense role for Uber. Spero is presiding over a suit where Quinn lawyers represent defunct ride-hailing service Sidecar, claiming Uber effectively priced Sidecar out of the market. In the earlier case, Yellow Taxi v. Uber, Quinn helped Uber fend off claims from a Maryland taxicab company that claimed in 2014 that Uber was illegally sidestepping local taxi regulations.

Spero said the Maryland case, like the one he's overseeing, involved antitrust claims, claims that Uber caused drivers to charge predatory prices, and claims that the company's actions amounted to an attempt to monopolize the for-hire transportation market.

“All those things seem to me to show pretty clearly that that case is substantially related to this case,” Spero said. “It is, to me, an entirely irrelevant question that it's taxi drivers [in the prior case] and that it's an app here. We're talking about Uber's behavior.”

Spero also took issue with language included in declarations by Quinn lawyers, including firm co-founder and chairman John Quinn, which said that they “had no particular recollection” of discussing antitrust issues that in-house lawyers at Uber claimed the firm had advised on.

“My presumption has got to be that if the lawyer doesn't remember it and the client does, that the client is right,” Spero said.

Uber's lawyers at Gibson, Dunn & Crutcher filed their motion to disqualify the Quinn lawyer in February. Uber contends that Quinn Emanuel represented it in at least 20 cases from 2012 to 2016 that delved into competition issues similar to the ones in the Sidecar case.

Quinn Emanuel's Robert Feldman at Friday's hearing pointed out the Yellow Taxi case Quinn handled for Uber was filed in July 2014 and was dismissed shortly thereafter. “The cases are clear that Your Honor should consider the nature and extent of the lawyers' involvement,” Feldman said to Spero.

Spero shot back that Quinn obviously had “direct involvement” in the case as defense counsel.

Feldman didn't shrug off the firm's role, saying that it “was absolutely our case.” But he did contend that the pricing issues in the Maryland case were different. The Yellow Taxi case, he said, dealt with Uber's refusal to comply with taxi regulators, rather than Sidecar's allegations of undercutting prices to eliminate competition.

Feldman also took responsibility for the “no particular recollection” language in his colleague's declarations, saying that he asked them to include it because there was “no substantiation and no detail in the submissions by Uber.” He said that declarations by Uber personnel that Quinn lawyers had provided general antitrust advice were couched in generalities, offered no specifics and amounted to “simply hand-waving” compared to the details his colleagues offered.

Arguing for Uber, Gibson Dunn's Theodore Boutrous Jr. said that Uber's lawyers weren't required to disclose privileged, confidential material in order to make the case their former lawyers should be disqualified. He said that Quinn's prior work analyzing whether California's Public Utilities Commission had jurisdiction over Uber was particularly problematic since the CPUC's jurisdiction over the company could be raised as a defense in the Sidecar case.

“Here the substantial similarity is clear from the face of the complaint and the briefing that Quinn Emanuel drafted,” Boutrous said.

Spero took the motion under submission Friday and said that he would “get into the weeds” of the underlying exhibits and declarations before issuing a decision.