To his credit, Strange has figured out that Rita's spectacularly a one-trick pony. She's using fire, more fire, even more fire, and fire on top of that. The easiest thing to do would be to cast a water spell and just knock her out that way...except for the fact that Strange doesn't know any elemental magic to begin with. That's lesser magic, the magic of warlocks and changelings. But it would be damn useful right here and now.

And good Lord that is a lot of fire. Strange drops to the ground in a crouch, casting the barrier spell right over him, like a turtle going in a shell. Thankfully, that prevents Rita's ring of fire from entirely setting him alight. Unfortunately, the back of his coat is straight up on fire. Still staying close to the ground, Strange shrugs the coat off as he quickly decides what to do next.

He's equally a bit of a one trick pony as Strange keeps defaulting to force bolts. Rita hasn't shown any defensive magic, if he keeps knocking her over and keeps having his barrier spell at the ready, he'd win in the long term. This time, however, there's a quick one aimed at Rita's head, followed by another quick one aimed at her feet.