The women's Black Sticks have pulled off a stunning upset in their opening group game, thrashing the highly-touted Argentina, 3-0.
The world no.2 ranked Lioness' dominated long periods, but the Kiwi defence held firm, with a little help from the goal post with Argentina hitting three shots off the bar.
Third quarter goals for Kelsey Smith and Hope Ralph gave New Zealand the upperhand against the run of play, before Holly Pearson put the game to bed in the final frame with a cracking shot from inside the circle.
Earlier, New Zealand swimmer Lewis Clareburt missed out on a medal in the pool at the Tokyo.
Competing in the men's 400m individual medley, Clareburt - the second top quaifier for the final - was second turning for home on the final leg. but faded late to finish seventh.
The race was won by American Chase Kalisz, from countryman Jay Litherland and favourite Brendon Smith.
Clareburt was well-placed after the butterfly leg and led briefly after the backstroke, but Kalisz powered to the lead during the breaststroke leg, heading Clareburt after 300m.
The Kiwi made some in roads in the first 50m of the freestyle, but after the turn he ran out of steam for a seventh place finish.
Clareburt finished in a time of 4:11:22, two seconds slower than his sensational heat performance on Saturday night.
Had he matched that performance he would have claimed a medal.
A gutted Clareburt says he did all he could to be prepared to swim fast.
"I did everything I could to put myself in a good position to swim fast this morning and I just couldn’t," Clareburt says.
"It was tough. What hurts more, if I had done my time in the heat in the final… it would have been enough."
Clareburt was hoping to break a 25-year drought in the pool for New Zealand, with Danyon Loader the last swimmer to claim a medal with his double-gold's in 1996.
And it was a great opening day of competition for New Zealand's surfing duo. Ella Williams earned direct entry into the final 16 with a second place finish in her heat.
Billy Stairmand had a slightly lengthier journey after finishing third in his heat he had to go through an elimination round and his third place finish was enough to book a spot in take knockout stages.
Meanwhile, Emma Twigg coasted into the semi-finals of the women's single sculls, dominating her quarter-final, finishing with the fastest time.
The women's double sculls qualified for their final with a second-place in their semi-final run, but the news wasn't good for three other Kiwi boats.
Single sculler Jordan Parry was eliminated from medal contention with a fourth-place finish in his quarter-final, while the women's quad are also out after finishing third in the repechage.
Men's double sculls crew of Chris Harris and Jack Lopas are also out of the medal hunt, finishing fourth in their semi-final.
And men's 68kg taekwondo's Tom Burns lost 53-8 in his first round bout against second seed Brit Bradly Sinden.
Elsewhere, surfer Billy Stairmand finished third in his shortboard men's surfing competition qualifying round, meanning he will have to go through a second round of qualifying to make final.
Luuka Jones is 10th after her first run in the K1 canoe slalom - the Kiwi has a second run later on Sunday, needing to finish in the top 24 to qualify for the semifinals.
And shooter Chloe Tipple is struggling in the Women's skeet shooting comp. The Kiwi is 28th and last afer three of five rounds.
Plenty more Kiwis are in action throughout Sunday, with the highlight being the OlyWhites second group match against Honduras.