Two major upsets have highlighted quarter-finals day at the New Zealand Tennis Championships in Auckland.

Defending champion Artem Sitak was ousted in straight sets by one of the brightest prospects in the men's game, 17 year old Macsen Sisam.

The young Aucklander was aggressive was the start and overcame the experienced ATP doubles specialist 7-5, 6-4.

Sisam will play Olly Sadler in one semifinal after the third seed thrashed seventh seed Finn Reynolds 6-1, 6-4.


The other semifinal will pit top seed Finn Tearney against wildcard Anton Bettink.

Tearney rallied from a set down to beat Rob Reynolds 3-6, 6-2, 6-1 while Bettink also fought back from losing the first set to beat fourth seed James Meredith 3-6, 6-3, 6-2.

By contrast the women's quarter finals were fairly straight forward.

Top seed Joanna Carswell cruised past eighth seed Elys Ventura 6-1, 6-4 and will take on third seed Sacha Jones in one semi after the ex WTA tour player crushed fifth seed Oleksandra Kalachova 6-2, 6-0.

Fourth seed Katherine Westbury was equally impressive in thumping sixth seed Nina Paripovich 6-1, 6-1. Westbury will take on seventh seed Emilia Price for a place in the final after she beat Louise Waite 6-1, 6-4.

The tournament moves to the ASB Tennis Arena for Friday's semi-finals and Saturday's finals.

The first match on centre court between Jones and Carswell gets underway at 3pm followed by the two men's semi-finals. The second women's semi-final is on court 4 from 3-30pm.