"I really want to do well and I hope my performance is good enough. Experience allows me to trust in my performance and preparation, because it's very scary out there."
The time was one of the fastest of Carrington's career though not as slick as her world best 37.898sec set in Moscow two years ago.
Her coach Gordon Walker believes Carrington had the best conditions of the three semi-finals so was reading little into time comparisons.
The field will include four of the top five finishers from the London Olympic final four years ago, including silver medallist Inna Osipenko-Rodomska of Azerbaijan. The 33-year-old clocked 39.803sec to be the second-quickest qualifier.
Carrington responded brilliantly in the third and final semi-final, blasting from the blocks and giving her rivals no respite throughout the sprint journey. Spain's Teresa Portela Rivas was second, two-thirds of a length back.
Earlier, there was disappointment for teammate Marty McDowell, who failed to advance when finishing seventh and last in his men's K1 1000m heat.
McDowell never came close to the top-five requirement to advance to the semi-finals. He was fourth through the first 250m but had slipped to sixth by the halfway point and only lost ground from there.
His heat was the fastest, won by Portugal's Fernando Pimenta. Walker says McDowell wasn't far off his best.
"Marty's in a tough game, those were the fastest heats I've seen," Walker told NZ Newswire.
"It wasn't his best ever race but it wasn't bad by any means. He'd have had to be at his very best just get out of the heat."
McDowell and Carrington both arrived in Rio after training camps in Portugal and Spain. Carrington showed promising signs in her heat, taking control from the outset to claim a comfortable win in 40.422sec, a boat length ahead of Portugal's Francisca Laia. Four-time world champion Carrington hasn't lost in the event in five years and has won at her last 13 major international regattas.
Carrington has also entered the K1 500m in Rio and is seeking to become the first Kiwi woman to win two gold medals at the same Olympics.
Conditions were hot and still at Rodrigo de Freitas lagoon, the venue used for the previous week's rowing regatta.