New Zealand edged host nation Japan 2-1 in a tight pool B match in the women's hockey tournament at the Toyo Olympics.
Second-quarter goals from Olivia Merry and Hope Ralph were enough to top a game Japan side that took a first-half lead.
Shihori Oikawa's penalty corner shot early in the second quarter stunned the Kiws into action, who despite dominating possession, failed to create any chances of note.
But New Zealand scored from their first penalty corner midway through the quarter after a Merry bullet smashed into the bottom of the net.
Merry turned provider for the second-goal minutes later, crossing from a deflected shot into the path of Ralph, who scooped the ball past the keeper.
But Japan dominated the final half-hour, creating several goal-scoring chances through penalty corners, but were continuously denied by the outstanding Kiwi stopper, Grace O'Hanlon who made four tidy saves of note.
The Black Sticks lacked any creative intent in the final 15 minutes, happy to defend and counter against an aggressive Japan side.
The win lifts New Zealand to second in their group, behind Australia with their thirid game of the tournament on Wednesday against Spain.
Meanwhile, teenage swimming star in the making Erika Fairweather has shined again, qualifying for the 200m freestyle semifinals.
Just hours after lining up in the final of the 400m freestyle, the Dunedin youngster achieved the 14th best time in the heats on Monday night, recording a 1:57:26, two seconds behind top qualifier Katie Ledecky.
It wasn't good news for New Zealand's 1500m freestyle swimmers with Eve Thomas and Hayley McIntosh failing to qualify for their final.
The Kiwi pair swam in the same heat, with Thomas coming home fourth and McIntosh sixth.
Both recorded times well below their personal bests with Thomas' 16:29:66 six seconds down on her's and McIntosh (16:44:43) 16 seconds down on her PB.
And the All Blacks Sevens side has started their Olympic campaign in style, backing up Monday morning's thumping of Korea with a 35-14 win over Argentina in the evening session.
Up next is Australia on Tuesday afternoon with the quarter-finals set to go around 8:30pm tonight.
Tueday's Kiwi action:
BOXING
Men's heavyweight round of 16 - David Nyika v Youness Baalla (Morocco) 3:51pm NZ
CANOEING
Women's K1 slalom semis & final - Luuka Jones 5pm & 7:15pm NZ
FOOTBALL
Women's first round - Football Ferns v Sweden 8pm NZ
HOCKEY
Men's Pool A - Black Sticks v Japan 2:45pm NZ
SAILING
Women's 49er FX, Races 1, 2 & 3 - Alex Maloney & Molly Meech 3:05pm NZ
Men's Laser, Races 4 & 5 - Sam Meech 3:15pm NZ
Men's Finn, Races 1 & 2 - Josh Junior 4:05pm NZ
Men's 49er, Races 1, 2 & 3 - Peter Burling & Blair Tuke 5:50pm NZ
SEVENS RUGBY
Men's pool round - All Blacks Sevens v Australia 1:30pm NZ
Men's quarter-finals - All Blacks Sevens 8:30pm NZ
SWIMMING
Women's 200m freestyle semi-finals - Erika Fairweather 12:30pm NZ
Men's 800m freestyle heats - Zac Reid 11:37pm NZ
TENNIS
Men's doubles second round - Marcus Daniell & Michael Venus 2pm NZ
TRIATHLON
Women's individual - Ainsley Thorpe & Nicole van der Kaay 9:30am NZ