She's not gonna beat Thanos in a one on one fight... Feige is lying to y'all...
Unless I missed something I don't think he never said that. I don't think he said anything even remotely similar to that.
He said she'll be the strongest character in the MCU. Which by itself means nothing. Feige has said Hulk is stronger than Thanos, but he lost the fight because Thanos is a better fighter. He's more strategic. So being the strongest don't necessarily mean an easy win.
Fred.