Lucy from the manga version of Elfen Lied vs. Manchester Black from Action Comics # 775/Superman vs. the Elite. Morals off (not that it matters) and a random encounter. They start four meters a part from each other.
That's not saying much since Supes never kills, and Lucy has killed many. Not sure how Manchester would feel about having his body cleaved into pieces by invisible vectors. Sure he has some decent psionic powers. Lucy, going all out, could effectively destroy the world. She'd only need to for about a second as hundreds of high-hypersonic vectors tore through Manchester's body.
I never said she had a planet-busting attack. I said; "Lucy, going all out, could effectively destroy the world". That doesn't mean blowing up the planet. That means bringing such destruction that life is effectively ended. Her vectors were tearing across the length and breadth of the planet, destroying cities, and nothing could stop them. The cost, however, for ending all of humanity would mean killing herself from the rapid deterioration of her body from exerting so much power. However, that's only if she continued to use it excessively. If she only needs that level of power for an instant to kill one guy? Then she'll be fine.
Lucy's vectors weren't powerful enough to destroy the planet in an instant. However they did manage to cover most of Japan at a high rate of speed causing massive damage. It also important to note that the person causing damage in that scan is the third persona of Lucy known as the Genocide Engine. Which is more psychotic than the original Lucy. So even though Lucy is not technically a planet buster, she will be able to dish out more than enough damage to Manchester Black to take the win here.