The Thing knocked out Atlas in a proof of crap writing.
Atlas himself is more powerful than the Thing.
When he reach his 60 feet size, he's a high Class 100 of Strenght possessor, also he can give major troublems to Juggernaut, but it also depends on which version of Atlas we pick up.
If we choose the version equal to Wonder Man, able to fly, 15 feet tall, and shining of red ionic energy, he can stay against Juggernaut without much problems.
If we choose the version that was hundred of feet tall, and was causing earthquakes just walking on the ground, he can stomp Juggy then throw him into outerspace.
Classic Atlas will show his own and then fall down, unless he pick up Juggy and throw him in outerspace.