JACKSON, Miss. — The chief justice of the U.S. Supreme Court interrupted with questions several times Wednesday as four Mississippi law students argued a practice case before him and other federal and state judges.

In the Mississippi Supreme Court chamber, the judges listened to about an hour of arguments in a moot court case about corporate negligence. When the judges left the room to evaluate the case, the audience of other judges, lawyers, law school teachers and fellow students applauded.

Back in the courtroom a short time later, Roberts said the students argued well under pressure.

“Other than that last part about everybody applauding, it was a very realistic duplication of what we do in Washington,” Roberts said.

The chief justice said he lost his first moot court case when he was a law student at Harvard.

The judges decided that the team from the University of Mississippi, James Kelly and Meredith Pohl, prevailed by a narrow margin over the team from Mississippi College, Patrick Fields and Lindsay Roberts.

One of the students mentioned in his arguments that a witness in the case had been given immunity from prosecution in exchange for testimony.

“Not relevant at all, but a very good thing to mention because nobody likes a snitch,” John Roberts deadpanned to laughter from the audience.

Roberts, 62, swore in appellate court staff attorneys and law clerks to practice before the U.S. Supreme Court, and met with Mississippi appellate judges and staff.

Roberts, who has led the nation’s highest court since 2005, was in Mississippi to mark the bicentennial of the state and its court system. Mississippi created its court system when it joined the union in December 1817. In a speech Wednesday night to more than 500 lawyers, judges and others, Roberts focused mostly on the history of federal courts in Mississippi, but also noted state courts are key to justice.

“The overwhelming portion of any legal business has always been handled in the courts of our states,” Roberts said.

Mississippi Supreme Court Chief Justice William Waller Jr. also addressed the banquet, focusing on the importance of courts to uphold laws.

Waller called for Mississippi to expand its system of county courts, which only some counties now have, and for state courts to complete their transition to a unified system of electronic records.