What's Doomsday's ability to hit got to do with anything? Grab the non-flying bad guy. Punch, kick, headbutt, and grapple. While doing so, fly into space. Achieve escape velocity with the ease of blinking. Get a couple light-minutes away from the earth. Disengage from grapple, position badguy between self and sun, toss a punch, allow momentum to take over.
There is absolutely nothing Doomsday can do to prevent this; even grabbing Clark and not letting go isn't sufficient, because all Clark has to do is get one picosecond of freedom to act, and they were evenly matched enough that he could have achieved that.