She ran her first-round race of the women's 1,500 meters in 4 minutes, 11.25 seconds. That ranked 21st in the 45-runner field, but fell 3.42 seconds shy of qualifying for the Wednesday night semifinals.
"I definitely gave it my best shot," said Muncan, "but I was running against the greatest women in the world. They're all such fabulous athletes. I was hoping to place higher and make it into the semis.
"There was a lot of change of pace and surging, that really hurt me. I should have been prepared for that," said Muncan, whose best time coming in was 4:06.48.
"But at the end of the day, here I am running in the Olympics for the first time, and I'm very happy to be here."
Former Villanova teammate Sheila Reid, twice an NCAA cross-country champion as well as NCAA outdoor titlist at 1,500 and 5,000 meters, will run the 5,000 for Canada starting with the Tuesday morning qualifying rounds.