ZAC Purchase cut down the Kiwi world under 23 champions to power into tomorrow's semi-finals at the World Cup Regatta in Amsterdam.

The King's School Worcester product was joined by Wormington's Alex Gregory in the next round as his GB quadruple scull crew chased home Poland to grab the second qualifying slot.

World lightweight single sculls champion Purchase was trailing at the 1,000-metre halfway mark with lightweight doubles partner Mark Hunter before bursting through to win by a two-length margin.

"We didn't quite nail the rhythm in the first-half, but once we got it going we cruised through them," said 21-year-old Purchase.

"It was a bit scrappy perhaps, but we won with something to spare which is what it's all about in the heats.

"The Kiwis are no mugs - world under 23 champions - but they probably went off too hard and once we got into it, we had too much for them."

Purchase, who took the world singles title in record time at the London 2012 regatta lake last September, has teamed up with Hunter to pursue Olympic glory in the Games class double.

First time out in Linz, Austria, three weeks ago, they surprised even themselves by taking silver behind world champions Denmark.

"Yes, we've started well, but we've only been together a few weeks so every time we row and race, it's a learning process," added Purchase.

"We'll need to tidy things up, but we were fairly comfortable at the finish and it's game on for the semis."

GB broke the Kiwis' resistance at the 1,250m mark and were already clear water up by 1,500m, easing home 3.7 seconds clear in six minutes 28.06 to take the sole direct qualifying slot.

Gregory's quadruple scull powered through Holland in the last 500m to assure a semi-final slot.

Worcester RC's Matt Beechey races on Sunday in the men's lightweight pair, having taken bronze three weeks ago in Austria.