About the only people out at Eton Dorney whose jaws weren't dropping round their ankles about the opening day Olympic rowing performance of the Kiwi pair were the two blokes in the black singlets responsible for it.

Never mind that the triple world champions had just scraped six seconds off the world's best time in the men's pair - a mark set by Brits Matthew Pinsent and James Cracknell that had stood for a decade.

Never mind that they took that scorching time and made it look like a Sunday row-about on the local pond when they won their heat by nearly nine full seconds.

As far as Eric Murray and Hamish Bond are concerned, they ain't done nothing yet.

Last time they looked, no one hands out medals for heat wins, no matter how impressive they are.

And theirs was as impressive as it got on a sizzling day out in Buckinghamshire when ideal conditions and a fast course saw a handful of record marks broken.

"We just wanted to go out and put our preparation into practice," said the 29-year-old Murray soon after the race that had everyone talking out at this purpose-built venue west of London.

"It's one thing saying 'yeah, we're really well prepared going into an Olympics', then there's another thing to actually go out and show how well prepared we are.

"I think we've done that, but this is only the heat. We're under no illusions. We just wanted to go through each step, so today was just about getting across that line first and qualifying for the semifinal, and that's where we're at right now."

But surely, after streeting their heat in an almost unbelievable time of 6min 08.50s - the mark set by Pinsent and Cracknell had been 6:14.27 - there must be an element of satisfaction? Especially considering the next swiftest crew, the Brits, have eight seconds to make up from somewhere.

"We knew we were well prepared but to see how it will materialise over a 2k run, you're never quite sure," added Bond.

"So it's given us a confidence boost for sure going into the next races. We know we're fast. We've just got to keep smacking out the races like that one and make sure nothing troubles our rhythm."

But Bond, too, shrugged off the significance of their time as they chase a 16th straight major title to complete a perfect four years since they came together in this boat in 2009.

"I knew it was fast conditions, but you don't really have a great sense of how fast you're going down the course," said Bond.

"I had an inclination we going fast but like Eric said there are no medals for heats unfortunately."

The pair - the surest things at this regatta - will race their semifinal on Wednesday, and if opening day was anything to go by their rivals are all gunning for the medals made of silver and bronze.

Nearly as impressive, and certainly more of a surprise, was a top-class effort from double-scullers Nathan Cohen and Joseph Sullivan as they beat the Olympic record (previously 6:11.49) en route to a heat win, and fastest time, of 6:11.30s.

Considering they were floundering round at the back of the field in the Lucerne World Cup regatta a matter of weeks ago, this was a hugely impressive display from the back-to-back world champions who look back on course for the Olympic gold.

"It's great," said Cohen, who's very much the senior figure in this special partnership.

"It's always nice to win a race and especially win one at the Olympics, and we're very happy first up to get that first race done.

"There was no need to panic for us after Lucerne. We know we've done the work, and the result [there] probably didn't show where we were at. We just had a few little things we had to get back together, but it's good to be competitive and right in the middle of that mix."

Sullivan said they had not been foxing as they sat back in third through the first 1500m, and called on a blistering final 500 in which they out-finished Brits Bill Lucas and Sam Townsend with a 1:30 final split.

"We're not the fastest starters in the competition. We went out and kept our race to ourselves with what we planned. We pushed where we needed to and felt we were in contention the whole time. We know we're good over the last 500m and gave it a bit of a push and it came through."

Completing an outstanding opening day for the big-hitters in the New Zealand men's squad, single-sculler Mahe Drysdale flat out cruised to an 11-second victory over Olympic champion Olaf Tufte of Norway to head into Tuesday's quarterfinal with his confidence high.

The 33-year-old five-time world champion was the second slowest of the six heat winners, but he shrugged off the significance of that on a day when most kept plenty up their sleeves.

"I had goals," he said afterwards.

"No 1 was to win that race, No 2 was definitely to have a really good first 1000. In the heats that's important to get a good blowout. It went well, I got a very clear lead, and at the end I was still cruising.
"You don't want to waste everything right now."

- © Fairfax NZ News