I think for the most part Loki is still a good match for her, usually he always has issues when his schemes are uncovered and he is faced directly. He is powerful enough on his own given his innate godly strength and his magic ability and has been able to beat the Thor Corps. around, hold his own with Thor at times and so on but most of the time he can be bested once he is confronted. That being said his plotting is a rough thing to overcome.