Mami Karino's third minute goal proved enough for Japan to clinch a surprise Pool A triumph at the University of the Witwatersrand.

After Karino had opened the scoring early on, the Japanese team held firm in defence as they strengthened their chances of qualifying for the next round with a narrow win.

England, whose team featured several of the players that sealed Olympic gold in Rio de Janeiro for Britain last year, put in a disappointing performance and now sit fourth in the pool.

Japan remain unbeaten and moved up to third behind Olympic bronze medallists Germany and Ireland.

"Credit to Japan," England coach Danny Kerry, who guided Britain to the Olympic title at Rio 2016, tweeted after the match.

"They started fast and took their chance and then defended brilliantly.

"We will bounce back."

The Irish team currently occupy top spot as they built on their draw with Germany in their opening match by beating Poland 2-0 to book their place in the last eight.

Ireland came into the contest full of confidence and they did not have to wait long to take the lead as Nicola Evans found the net in the 10th minute.

Gillian Pinder then wrapped up victory as she doubled Ireland's advantage in the second half.

In Pool B, India picked up their first win of the tournament as they edged Chile 1-0 in a low-scoring affair.

Preeti Dubey got the game's only goal in the 38th minute to ensure India, who recently pulled out of the new Hockey Pro League event, finally got their campaign up and running.

Argentina, the defending champions and three-time Champions Trophy winners, survived a scare as they recovered from a goal down to beat hosts South Africa 3-1.

The men's tournament resumes tomorrow, before the next round of women's matches take place on Friday (July 14).