Tietjens has been coaching the national side for a remarkable 20 years since the Hong Kong tournament in 1994.
He says the significance of the milestone struck home after his team's win in Hong Kong late last month.
"My first tournament win as New Zealand coach was winning Hong Kong in 1994 and then winning it in 2014 made it quite significant," Tietjens said.
"Winning just three weeks ago was quite special 20 years after the first."
Leading into the final two legs of the series is a situation Tietjens has been in many times before but he says it does not make it any easier.
"It is always tough. These two tournaments are about wining or losing the World Series, really, and we have a pretty tough pool in Glasgow in South Africa, Samoa and Portugal. Mate, it is not a given, that's for real. If we trip over and don't make the cup championship, it is all on."
Tietjens has guided his teams to 11 of 14 World Series wins.