Black Watch brought America to its feet. In the end, even with a slightly adapted script, extra preparation for its actors on their diction and pronunciation, and understated but real concerns over whether the play would be understood, John Tiffany need not have worried about his masterful drama at all.

The first night of Black Watch in the US, which debuted at the Freud Theatre in Los Angeles early yesterday morning in UK time, was a resounding success.

Greeted with some very Californian "whooping", real tears and a very un-LA standing ovation, Gregory Burke's work began its first theatrical run outside the UK to rich acclaim from the audience.

Although the official reviews, barring one exulting article from Newsweek, are not due until later this week, the audience that stood loudly applauding the piece in the theatre on the UCLA campus left the building eager to talk about its virtues.

And best of all for the National Theatre of Scotland: they understood it.

Tiffany, the play's director, and the actors have been working all week on slightly slowing down the speed of delivered speech, of clarifying some of the accent and changing some words which have a different meaning in the US (such as "fanny", which means "backside" here, and "pissed", which means "angry") for its new audience. But the play has not been sanitised: the changes are largely subtle and technical.

Indeed, a preview in the LA Times said the work "bodes to set a Los Angeles stage record for Anglo-Saxonisms per minute" and contains "a fusillade of swear words that makes David Mamet seem almost prim".

"I had no problems at all understanding," Californian native Maureen Krutonog said afterwards, as she discussed the performance with her partner, Boris, "and it was amazing for us to see the war discussed from another country's viewpoint. I thought there were some terrific performances. I thought it was really interesting to see the story of the regiment and its history, the sense of the soldiers fighting for their brothers. In the US, regiments are made up of guys from all different areas, not just one place like the Black Watch."

Boris, however, added: "To me, although I enjoyed it, it was too much on the nose'. It was visually very impressive and it was entertaining. But I know war is terrible, that people die in wars and it's bad. So for me what it presented was the obvious: I'm still waiting for a deeper meaning in there."

Maureen noted: "As far as the language is concerned, I quickly became used to the C-word. It was fine."

Tiffany revealed after the show that the script, apart from obvious changes made for US audiences, also includes new lines, adapted from the recent BBC radio version of the play. There is a new, and very funny, reference to the content of the pornography stashed by the troops in their Warrior vehicle, and also more joking references to the comparatively well-equipped US army.

Cynthia McDermott was not alone in being in tears after the show.

"That was one of the most amazing things I have ever seen," she said. "The history of the Black Watch, its pride and motivation, was very obvious. I think it will prove to be a very important play, especially here in America, which is really so isolated. It is educational and moving, but I absolutely enjoyed it, too."

Judy Maldonado, 33, and her friend, David Mertl, 24, noted the humour in the show in particular and said it would appeal to a younger audience than may see it at the UCLA Live festival, of which it is now part.

"I think how the audience in the US will react will depend on that audience and what they are usually used to," Ms Maldonado said.

"The swearing and the pornographic images used by the soldiers - they are pretty in-your-face. I heard intakes of breath. It is a little shocking."

Mr Mertl added: "I just didn't know about the Black Watch, about its tradition. From the US perspective, we have thousands and thousands of troops over there in Iraq, to have three people die is a daily event. But in the play, of course, it was very moving."

A group of US Iraq veterans present at the show also thoroughly enjoyed it, and commented afterwards on the shared experiences of soldiering: the obsession with food, with comradeship, and were unperturbed by the frequent jibes at the US military contained in the play.

Bob Navarro, an older veteran of two tours of duty in Vietnam, said: "I think the audience took a tour of Iraq with the Black Watch tonight. It had quite an impact on me. I felt I was right back there. The language of the soldiers? That's just how they speak. I remember that so well. That's just how the guys talk." His wife, Irene, added: "I will recommend to everyone that they see it. But not to children."

Mary Jo Catlett, in the audience with her friend, Lee Melville, was inspired by the intensely physical performance of the cast.

"I thought the play was just amazing," she said.

"The discipline of the actors is extraordinary - they must be bruised from head to foot.

"The scene where the history of the Black Watch is explained in one go, through the changing fashions of the uniform, was extraordinary, too. The ovation was great, but this is definitely one play where the audience should be standing at the end."

She added: "I do admit it took five minutes to get used to the accents, but that was all. And the language? I have no problem with it. The language is authentic and real."

Holly Wallace, the publicist for UCLA Live, was surprised by the standing ovation. "LA audiences can be very jaded," she said.

"Ovations are not common at all, so that was something really impressive. To move people like that, to make them get up off their feet? That's a big deal."

"I couldn't be happier about it," Tiffany said afterwards. He was particularly glowing about the performance from the actors.

Tonight is the invitation "first night", when it is rumoured some stars may be turning up to watch the show.

The Herald will be there to see them.