Australia eased to their second successive victory, taking their goal tally into double figures with a 5-0 victory over Pool A opponents Spain.
World number ones Australia stepped up a gear from their 6-0 win over South Africa and were ahead early on when Russell Ford produced an expert near-post finish from Mark Knowles' pass.
Matt Butturini added a second with a shot on the turn and Simon Orchard converted Matt Gohdes' cross to make it 3-0 at half-time.
A brilliant 50-yard aerial ball out from the back by Chris Ciriello sent Glenn Turner racing through to score the fourth and then Edward Ockenden deflected in Ciriello's slapped pass from a penalty corner, with defender Ciriello then hitting a post with another set-piece.
New Zealand's first win of the Olympics severely dented the medal hopes of eight-time champions India after their second successive defeat.
Andrew Hayward was the key man in the Black Sticks' 3-1 win as he scored one penalty corner, created another from a set-piece and also hit the post on one routine.
New Zealand's first points put them back in touch with the upper reaches of the group, although they remain three behind leaders the Netherlands, who overcame Belgium 3-1, in Pool B.
Great Britain escaped with a late 2-2 draw against South Africa after it seemed they would pay dearly for not making the most of their early advantage.
Having taken the lead through Ashley Jackson's penalty corner, they were staring at a defeat two minutes from time only for the East Grinstead midfielder to pop up with the slightest of touches to equalise with his second of the match.
Pakistan moved to third in Pool A - though only on goal difference - after recording their first win of the tournament against Argentina.
Germany continued their steady progress in Pool B with a narrow 1-0 victory over the Republic of Korea.