The 33-year-old arrived in Moscow ranked 95th in the world and clocked two hours 36.24 minutes, the best run since Mara Yamauchi's ninth in Osaka.
This was only Partridge’s second World Championships outing and having finished 24th in Daegu two years ago, the Scot was able to toast a job well done in the Russian capital.
She adopted a cautious strategy, going through 20km in 22nd but came home strongly and the heat started to take its toll on her rivals.
“I started off and I was way back and for a minute I did wonder if I had been a little bit too cautious,” said Partridge, who saw fellow Brit Sonia Samuels finish 16th in her maiden World Championships.
“It was just getting my rhythm going and I didn’t really think about the times or even paying attention to the kilometre markers.
"It was all about looking at the next person in front of me and trying to get past them and it was a proper race in that sense.
“There were bits that I wanted to run harder and I feel that I've run within myself and that there was more there."
Meanwhile, Kenyan Edna Kiplagat made history as she claimed victory in Russia, becoming the first ever woman to win back-to-back marathon world titles.
Kiplagat come home in two hours 25.44 minutes with Italian Valeria Straneo 14 seconds further behind in second and Japan’s Kayoko Fukushi completing the podium in third.