Tank knocked a stunning 10 seconds off her previous best time at the Washington-Dempsey Indoor Meet in Seattle, America.
She clocked 9:29.22 to finish 11th in a high quality field, which included world and European indoor 1,500m champion Sifan Hassan, who was running for Nike Oregan.
Former Plymouth College pupil Tank was competing for Utah University, where she is studying.
She was their top runner in the event and her time moved her up to fifth on their all-time best rankings.
It was seventh fastest by a British runner since the start of the year and best by an under-23 athlete.
Meanwhile, Erme Valley Harriers youngster Sam Yearling and Tavistock ultra running specialist Adam Holland both again impressed at off-road night running.
Having triumphed a couple of weeks ago at the Moonlight Flit at Wrangton, the pair again claimed victories at the Wild Night Run at South Brent.
Yearling won the five mile race in a time of 37.12 minutes, while Holland was first in the 10 mile event. He clocked 1:16.15.
First won in the 10 mile race was Plymstock’s Carla Haines, who clocked 1:35.50 to finish 10th overall.
Full results from the Wild Nigh Run can be found HERE