Luffy get oneshot by Thunder Bagua in Kuri, he also received Ragnaraku in chapter 1009-1010, also knocked outta the island in 1013, but the narrator didnt say Kaidou win.
Dragon Kaidou was incapacitated for a few pages from Luffy's G4 Kong Gatling, and then for a few pages as well in chapter 1010. But the narrator didnt say Luffy win.
So i guess the narrator still knows the true result but he becomes quite unreliable since he revised the result.