The pair booked a spot in their second successive Games final, shrugging off a slow start to burn off their three rivals in yesterday's repechage.
Coles said coach Dick Tonks "had a frown" when they returned to the sheds but then praised them for their composure after a sloppy opening which saw them a boat length down on the field after 250m.
Coles said the pair tactically live by the equivalent of an old Confucious saying: "It does not matter how slowly you go so long as you do not stop."
It relies on other crews tiring in the face of relentless pressure, as happened yesterday.
"Even though it looks like we go faster, we like to keep it even throughout the race and other people tend to drop off," Coles told NZPA.
"Our strength is our endurance so we really like to keep it even and then have a bit of strength at the end to wind up a sprint. Which we haven't had to do yet."
That will be reserved for Saturday in final which sees Olympic champions Georgeta Andrunache and Viorica Susanu of Romania start as hot favourites from the other heat winners, world champions Yuliya Bichyk and Natallia Helakh of Belarus.
Coles agreed they were the crews to beat but took confidence from beating the Romanians home when they were second in the final World Cup race at Poland in June.
"They have really upped their game over the last two months but once we've beaten a crew, we always think we can beat them again," she said.
"We've beaten Belarus before as well and China in the heats."
The Poland performance followed by some exhausting sessions on Lake Karapiro -- including one unforgettable Tonks session of 40 consecutive one-minute bursts with short intervals -- has both rowers confident of better than the sixth placing in the 2004 Athens Games final when they were a new combination.
They won the 2005 world championships title in Gifu, Japan, snared silver in 2006 at Eton but only managed fifth last year in Munich.
"Other crews have improved and we've had a few difficulties over that time ourselves, just ups and downs," said Coles, who believes they are in their best form since Gifu.
