Isinbayeva, 26, set a women's pole vault record on July 11 this year at the Rome Golden League with a height of 5.03 meters, one centimeter lower than her leap on Tuesday evening.
"The record just happened," the Monaco resident told reporters.
"Monaco is my home town and it's my first competition [in Monaco] since I've been living here. That motivated me."
Looking ahead to the August 8-24 Beijing Olympics, she said: "To win there I think I'll have to beat the world record again."
Isinbayeva has now broken the pole vault record 23 times.