A state judge in Manhattan yesterday vacated the conviction of a Queens man in the notorious 1990 gang mugging and stabbing that killed Utah tourist Brian Watkins on a subway platform as he tried to protect his mother.

Supreme Court Justice Eduardo Prado ordered a new trial for Johnny Hincapie, who has been serving a sentence of 25 years to life, but claims he was wrongly convicted, largely on the basis of a confession that Hincapie said was coerced and false.

Hincapie, one of seven men convicted of felony murder in the killing, was already likely to be paroled soon, but his lawyers said he wanted to clear his name.

The original incident, along with the Central Park jogger rape case a year earlier, helped to galvanize public concerns about out-of-control crime in the city.

Hincapie was among a group of teenagers who had come from Queens to go dancing at the Roseland Ballroom. At a 7th Avenue subway station, some of them tried to rob the Watkins family, in town for the U.S. Open tennis tournament, and Brian Watkins was stabbed in the chest.

Hincapie had confessed, but subsequently claimed he was at the turnstiles a level above the platform when the killing took place, and not part of the group that mugged the family.

At a hearing before Prado, three witnesses backed his story. They may testify if prosecutors decide to go ahead with a new trial.

Joan Vollero, a spokeswoman for Manhattan District Attorney Cyrus Vance Jr., said the office would review Prado's ruling to consider whether to appeal, but was committed to a retrial if the judge's decision stands.

"We remain committed to retrying the case, if necessary," Vollero said.

"We regret the fact that retrying the case would subject the family of Mr. Watkins to testifying at another trial, reopening old wounds and forcing them to relive the horror of that night 25 years ago."

Hincapie's lawyers had asked Prado to declare him innocent, clearing him of the charges. Prado declined to go that far, but did order him released as the case continues to unfold.