I think the point is that the more experienced (no way to determine how much more experienced) and skilled fighter was severely wounded and the newbie's instinct for survival allowed her to win this one....solitary...moment. A moment. Nothing presented in the film suggests she can A. do it again B. has peaked in her ability/skill or C. that Kylo Ren won't mop the floor with her if he is thinking clearly and at 100% physical condition. I think too many are clinging to the outcome of the fight and forgetting or choosing to ignore the conditions of said fight.
Not to mention that this trilogy is Kylo's story as well. It's been made clear in the end of TFA, as well as all the promo summaries for Kylo in TLJ, that he's still training. So it's kinda off to assume that Rey is just "amazing 4evr" because she got lucky and beat him when he was wounded and unfocused. I doubt she'd beat him at 100% in TFA, and he's likely going to be more powerful in this movie too.