I've seen lunatic Yuka get a spirit to the face with less than fifteen seconds of play in match mode, and then down to half an orb before two minutes in the same round. Of course she proceeded to beat me in four minutes and a half which is about as much as I can endure in lunatic match mode, but hey. What Freudia said is correct: the AI lives and dies by its speed.
Still, 1cc'ing lunatic is much, much, much easier than winning a single lunatic match mode round. I have 1cc'ed lunatic with Reimu, Mystia (three times - out of four!), Marisa and Cirno, and I think I've never won a single lunatic match mode round. As Baity said - last 2 minutes and a half on the second try from stage 6 onwards, don't panic against Shikieiki, hopefully you'll have enough lives to get a good run against her. The hotdog spams takes some getting used to but after you get the hang of it it's very fun, you need to micro- and macro-dodge on the fly which is great training at the very least.