Haughty Red Princess or not, a Blamp is nothing to scoff at, here's how I think it would play out:
Round 1 .... FIGHT!
Arianna immediately sets fire to the whole arena between her and Mavra, Mavra throws a bolt of black lightning that goes wide of the mark because of the distorted vision, meanwhile, Arianna whips up wind in a cyclone of air, directed more or less towards Mavra, Mavra's second spell, a firebolt, hit Arianna in the side, searing through her flesh mask and causing her immense pain. Mavra immediately draws her sword and starts to rush towards Arianna, but the cyclone of air is fanning the flames and turning them into a blazing inferno, causing her to hesitate. Arianna takes advantage of the time by pulling up a veil, and retreating from the arena to play a 2 hour hide and seek. Mavra attempts to pursue, catching a clue here and there but ultimately fails in finding Arianna in time, and with 20 minutes to go to sunrise, she decides to make herself a hideout to survive the sunlight, and the no doubt searching Arianna. She finds a clearing, layers it with illusions and digs a deep hole, using a spell to bury herself without a trace. A further proximity trigger will wake her up if Arianna stumbles into the clearing, with a couple of nastier traps set in.
At Sunrise, Arianna drops her veil, and takes time to heal herself and restore the damaged portions of the flesh mask. She starts to seek out Mavra, but realizes it won't be as easy as that, and she expects a few traps.
Mavra wakes up at sunset, no traps or alarms were triggered, and so she goes in search of Arianna, after a few hours, she finds Arianna in an area not far off of the original clearing. They sight each other almost at the same time, and Arianna starts raining firebolts at Mavra, Mavra negates them, taking a couple of hits and shrugging them off as she closed with impossible speed on Arianna, eager to put the upstart sorceress in her place.
50 feet from Arianna, she accidentaly triggers a trap, opening a portal into the NN. She tries to stop, but momentum carries her through to the NN, and into the middle of the Almightyish army, who destroy her as she attempts to escape.
Analysis:
Arianna did not spend the day searching for Mavra, she picked a decent spot with a 360 view, and positioned herself well, littering the area with hidden portals to the NN, and conserved her strength, waiting for Mavra to find her.