"I'm sorry we kept you in suspense until the very end," Sasaki said with a smile through a translator. "I tried to have a one-sided, stable game, but we always have these tense moments."
Mizuho Sakaguchi scored what could be the goal of the tournament by finishing off a beautiful passing play in the 78th minute to make it 2-0, but goalkeeper Ayumi Kaihori followed that up by completely botching Kirsten van de Ven's simple header in injury time to give the Dutch life and set up some nervy moments as they pressed for an unlikely late equalizer.
But defending champions Japan survived and will meet Australia in Edmonton on Saturday.
Silver medallists at the 2012 Olympics, Japan won each of its three group games by a single goal and did the same in the round of 16 against a young team from the Netherlands that was making its first appearance at a World Cup.
"It was an enormous stage, great stage to have been here," Dutch head coach Roger Reijners said through a translator. "It was a wonderful tournament, good quality players and it was marvellous to be part of it. We want to have more of the same. We will look back on this experience with great pride and pleasure."
Saori Ariyoshi opened the scoring in the 10th minute after Aya Miyama sent a ball in from the left that Yuki Ogimi headed off the crossbar. Dutch defender Merel van Dongen's flubbed clearance went right to Ariyoshi, who slotted a shot into the far corner past goalkeeper Loes Geurts from 15 yards out.
Prior to going down 2-0 on Sakaguchi's superb effort in the second half, the Dutch came close to tying the score, but Kaihori got a hand to a ball that deflected off one of her own defenders.
The Netherlands also had a great chance to take an early lead when Manon Melis moved down the left side in the seventh minute, but she completely whiffed on her attempt.
"We had a great start until it came to be 1-0 and then after 1-0 the Netherlands team was becoming a bit sloppy, with sloppy passing," said Reijners. "Our team did all we could to get something going and not leave with nothing at all. After 2-0 we were a little lucky and managed to make it 2-1."
The fourth-ranked Japanese, who will be matched up against Canada in the semifinals if both teams advance, dominated play in midfield most of the night. Leading 1-0, Ogimi jumped on a turnover in the 29th minute and tried a shot from distance that went wide before Shinobu Ohno saw her free header just flash past the post right before the halftime whistle.
The Netherlands, which is ranked 12th in the world and could have automatically qualified for the next summer's Olympics with a victory, came out stronger after the break, but weren't able to really threaten until the late flurry that left Sasaki apologetic.
Notes: All six of Japan's goals at the tournament have come from different players. ... Japan has won three games at B.C. Place Stadium in the tournament after picking up two victories in the group stage. ... Brazil, which lost to Australia in the round of 16, was the only other team other than Japan to go undefeated in group play. ... The Netherlands still has one last chance to qualify for the 12-team Olympic field by way of a European playoff.
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