Andrew Samonsky made his debut on Broadway the hard way.

Without so much as a New York minute of rehearsal, the Ventura native performed the leading role of Joe Cable in the revival of "South Pacific" at Lincoln Center.

Picked to understudy the part of the lovesick lieutenant who volunteers for a suicide mission, Samonsky had to fill in for three performances when Tony Award winner Matthew Morrison fell ill.

"It's the classic actor's nightmare. You dream you find yourself onstage and don't know the lines," said the 32-year-old Samonsky, who also performs the raucous "There Is Nothing Like a Dame" in the men's chorus.

In his waking hours, though, Samonsky had prepared in every possible way short of rehearsal. He knew Cable's lines cold and had his range-racking solos down pat.

And at 9 a.m. March 22, when the phone rang at Samonsky's Brooklyn apartment, he knew he'd be going on for that day's 2 p.m. matinee.

There was a minefield of potential gaffes awaiting him onstage, including a scene with a paring knife and a 10-second wardrobe switch.

Samonsky went into what he called "hyperfocus mode" as the stage manager walked him through the blocking.

He wasn't always so focused on the stage. The son of Susan, a teacher, and Louis "Chuck" Samonsky, a defense attorney, he played sports while at Buena High in Ventura.

After an injury sidelined him, he tried out for a school play and landed the leading role.

Undecided on a career path, he spent a year casting about at UC Santa Barbara, until voice coach Linda Ottsen encouraged him to pursue a stage career.

Samonsky then enrolled in the opera program at Cal State Northridge, and went for a master's degree in theater at UC Irvine.

Broadway bound

It was at Irvine that a professor convinced him to train as a tenor. The song he used as an exercise — "Younger Than Springtime" — happens to be Lt. Cable's showcase number.

When Samonsky received the invitation to audition for "South Pacific," he had never seen Rodgers and Hammerstein's musical adaptation of James A. Michener's epic tale of war and culture clash.

Despite a nagging head cold and tight turnaround time to get back to Denver, where he had just been cast in a regional production, Samonsky got himself to New York for the audition.

"To get a Broadway show, I would have played a blade of grass," he said.

Training, skills take over

He found himself wishing for that kind of obscurity as he climbed atop a sand dune, making his entrance as Lt. Cable.

"As I was walking up that dune, I remember thinking, Am I really doing this?'"

But once he spoke his first line, he said, his training and skills took over.

"It's customary and fun to physically push an understudy around the stage," said Kelli O'Hara, who plays Nellie Forbush, the naive nurse from Arkansas. "Andrew didn't give us that pleasure," she noted, saying she could not remember him making a single slip-up.

Samonsky's performance is the first O'Hara — who has been playing on Broadway for eight years — has heard of when an understudy assumed a major role with no rehearsal.

By the time his death scene rolled around at the end of the third performance on Sunday, Samonsky had come down from the adrenaline rush.

"When I was officially dead, what a relief," he said, chuckling.

Cast members applauded his efforts and the Broadway blogs were abuzz with praise for his performance.

Samonsky said he believes he benefited from low expectations. "As an understudy with zero rehearsal, as long as I didn't die out there, I was a hero."

tick, tick '

Theatrical producer Michael Jackowitz certainly had low expectations when Samonsky auditioned for "tick, tick BOOM!" at the Rubicon Theatre three years ago.

Jackowitz already had held auditions in New York for the lead role of Jonathan but was told there was a "Ventura boy I should see."

"I rolled my eyes and agreed to see him," said Jackowitz, who is producing the Rubicon's staging of "My Antonia" through June 1.

Jackowitz recalled going from an eye roll to a jaw drop.

"His voice soared and then when he read from the script we knew we had found our Jonathan. Home-grown and all," Jackowitz said.

The Ventura boy has resumed his place in the "South Pacific" chorus, but his time out of the spotlight likely will be brief, according to O'Hara, who earned her third Tony nomination on Tuesday, for her role in "South Pacific."

"I doubt he'll be an understudy much longer. He's a leading man, through and through," O'Hara said.

In fact, Samonsky just learned he will again play Cable while Morrison is on vacation during the week of July 22.