Nakhon Pathom: Thailand have to beat North Korea on Saturday to secure a place in next year's FIVB Volleyball Women's World Championship in Japan.
Thailand are currently on top of Pool B after winning their first two games against Iran and Vietnam.
At Nakhon Pathom Sport Centre Gymnasium, South Korea remained unbeaten after two matches, crushing Iran 3-0 (25-16, 25-18, 25-20) on Friday.
However, they remained in second place behind the Thais because of an inferior points ratio.
North Korea defeated Vietnam 3-0 (25-21, 25-22, 25-20) to stay third in the pool.
Thailand had a rest day.
Today's victory against North Korea will mean Thailand will be assured of a top-two finish in Pool B and earn a ticket to Japan.
The winners and runners-up from Pool A will claim the remaining Asian spots and join hosts Japan in the 2018 world championship.
"North Korea are very good defensively," said rising star Chatchu-on Moksri after the game against Vietnam on Thursday.
Veteran setter Nootsara Tomkom added: "Hopefully the fans will come out in full force and give us the support in the remaining two games.
"It is our most important game. If we can beat North Korea, we will go to the world championship next year.
"The match against South Korea is also important. We have two tough matches ahead. I hope for another full house because the support of the fans is very crucial."
The Thailand v North Korea match will be shown live on Channel 3HD (33) at 6.15pm. Channel 3SD (28) will broadcast the Vietnam v South Korea game at 3.30pm.
In Almaty, Taiwan beat Fiji 3-0 (25-9, 25-12, 25-10) to surge past China to the top of Pool A. Both teams have two 3-0 wins so far but the Taiwanese have a better points ratio.
Australia were due to play hosts Kazakhstan late last night.
Apart from five Asian teams, next year's world championship will also feature eight European nations -- Russia, Serbia, Turkey, Italy, Azerbaijan, Germany, the Netherlands and Bulgaria. South American champions Brazil and winners of a regional qualifying round, reigning champions the United States and six other teams from North America and African champions and runners-up will join them at the finals.