This is one of the challenges you have to complete in campaign mode. What you want do to here is knock them both out the house, but not out the arena. The house is the bulls eye target. What I did was position my power line between the red line given and the blue line, and then I threw, but didn’t use my sweepers immediately. I waited until I got past the first blue line to use my sweepers all the way to the max. It hit both of them out of the ring, but kept them from being knocked out of the ring. You don’t have to reduce them to zero points, just get them out of the blue circle for the achievement.