Michael McGlinchey and Shane Smeltz were both denied in one-on-one opportunities and Marco Rojas hit an upright after shimmying his way into the box.
There were anxious moments - Mark Paston pulled off one particularly good first-half save and El Salvador pressed in the dying stages as fatigue set in - but they had more shots on goal than the 'home' side and the pace of both Rojas and Barbarouses troubled El Salvador.
"That was probably one of the better performances we have put in, with a number of senior players not here and many players coming off six or seven weeks with no football," Herbert said. "It was a very young side against a team ranked inside the top 50 in the world.
"We had a couple of one-on-one chances that may have seen a different result but the biggest thing for me is that we played very well tonight. We passed the ball well, played with conviction and had good pace coming from the likes of Rojas and Barbarouses.
"It's pretty clear there's some exciting talent coming through and we just need to keep exposing them at this level."
They get another chance on Sunday when they take on Honduras in Dallas and Herbert has signalled he might switch from his 3-4-3 formation to a more conventional 4-4-2 but the main focus is the World Cup qualifiers starting in the Solomon Islands on June 1.
New Zealand are favourites to win the Oceania group and, if they can do that, will take on the fourth-placed team from Concacaf for a spot in Brazil. It's not inconceivable it will be against El Salvador, who are ranked third in Concacaf behind Mexico and the US, and there was little on show today for New Zealand to fear.
El Salvador were supposedly near full-strength and, while they were quick, skilful and moved the ball quickly - as you expect from teams in that part of the world - they were also vulnerable and could be dominated physically.
Their two goals today were also fortunate. The first, well finished by Rafael Burgos in the 14th minute when he beat Mark Paston to the ball just outside the box, looked suspiciously like offside and the second came about when Burgos' close-range cross was unluckily deflected in off Michael Boxall's foot.
It needs to be remembered the All Whites didn't win, and one against non-Oceania opposition is overdue, but if they emerged from a World Cup playoff in 18 months with a 2-2 draw away from home they would rate their chances of featuring at consecutive World Cups.
New Zealand 2 (Ian Hogg 27, Kosta Barbarouses 64) El Salvador 2 (Rafael Burgos 14, Michael Boxall OG 56). HT: 1-1.
