In her semi, Carrington was beaten to the line by an old rival, Hungarian Danuta Kozak. She won in 1:47.792, with Carrington recording 1:48.540, the pair producing the fastest times of the day.
Kozak is a double world champion at the distance, beating Carrington in both 2012 and 2013, but opted to race in team boats for much of last season.
She helped Hungary win world championship gold in the K2 and silver in the K4 in Milan last year, while Carrington created history by winning the 200m-500m K1 double.
Carrington is racing both distances in Rio, with the World Cup rounds an ideal chance to fine-tune preparation.
''The fields are super strong now and it's always good to race these girls," she said. ''It's really good practice, going through the nerves and the process of racing."
The women's K4 crew of Jaimee Lovett, Caitlin Ryan, Fisher and Kayla Imrie are through to their 500m final tonight after finishing third in their heat - good enough for a direct entry to the final.
They crossed in 1:32.513, behind crews from Belarus and France, and were almost 1s clear of fourth-placed Denmark.
New Zealand got off to a flier before world champions Belarus and the French got past them.
''We've been working a lot all summer -- in the gym, the pool and on the lake -- at being really fast off the line and it was really reassuring today to see us beat the world champions off the line and hold them off for the first 50m of the race," coach Rene Olsen said of the four."
The sole New Zealand male paddler going to the Rio Olympics, Marty McDowell, finished third in the K1 1000m C final in 3:33.093. He has been battling illness in the leadup to the regatta.
