"It was an amazing experience and it was great to get that sort of exposure against top-10 nations," Barham said.
The Futsal Whites, who are ranked 68th in the world, lost 2-1 to the 70th-ranked China in their first game.
"It was an even game. It was 1-all until the last 15 seconds. It was heart-breaking not to get the win because we had our chances," Barham recalled.
World No 3 Russia beat Barham and company 7-3 after leading 3-2 at halftime.
"The Russians are all fully paid athletes and we were winning for the first 15 minutes against them," Barham said.
Vietnam, who boast a world ranking of 20, beat the New Zealanders 7-0.
"Vietnam play a different style to us. They are the most technical team I have played against in my entire career. They showed me a lot of things I can use in my coaching," the 2017 national title-winning Central under-19 team coach said.
Barham was recalled for the China tour after not being required for international play for the previous 18 months. Before that spell he had played for the Futsal Whites for five years.
While he isn't coaching the Central under-19 team this year, Barham continues to coach the Napier Boys' High School team and he is assisting former Hawke's Bay tennis rep Mike Winkley with the coaching of the Napier Intermediate team which will compete in the 66-team boys-only division at AIMS in Tauranga in September.
"There are some really talented players in the team. They are sharp and I believe they will have a good chance of winning the AIMS title," Barham said.
This month he will play for Capital who, along with Otago, will be New Zealand's representatives in the Oceania Champions League. Next month Barham will be one of three Hawke's Bay players - Ethan Martin and Luke Maynard are the others - who will turn out for the New Zealand under-25 team at an international tournament in Kazakhstan.
New Zealand will start the 20-team tournament in the same pool as the Czech Republic, Belarus and the host country. The top two teams from each of the five pools will progress to post-section play.
Within a fortnight of the national team's return Barham will be turning out for Central in the national league.