Ronin Vs Atlas
At first this may seem like a very tricky fight for Maya but in reality it isn't, in fact atlas ability to increase his size will only make it easier for echo (don't get me started on the whole ronin thing

) to take her opponent out.
Lets go over her powers:
Maya Lopez is an olympic-level athlete possessing photographic reflexes or the uncanny ability to perfectly copy other people's movements, similar to the Taskmaster's. Just by watching other people, she has become a concert-level pianist, a dangerous boxer, and a gifted ballerina (and on one occasion even piloted a Quinjet for a few minutes). Aside from those, she has also gained Bullseye's uncanny aim and Daredevil's acrobatic abilities after watching tapes of their fights.
One of echo's favourite hobbies is watching kung fu movies to copy the styles of some of the greatest martial artists of all time. To fight echo is to fight bruce lee, jackie chan, jet li, stephen segal and even CHUCK NORRIS! Could Chuck Norris beat atlas, I think he could!
However, these powers will not be what she's using due to the sheer size and durability of atlas, the key here is a little human biology. Atlas is capable of massively increasing his size and therefore proportionate strength. Now at first this would seem like a major advantage, but not against someone with a keen knowledge of te pressure points in the human body. Think about it like this: I have studied martial arts for three years and in that time I have been tought various tiny points on the body where the pain of a stabbing motion or punch/kick is multiplied ten fold. Now these are very handy in a normal fight but require extreme accuracy. Not so when facing a giant as an area that would be the size of a penny on a regular human will be more like the size of cap's shield on a agiant. If you hit someone hard enough in these areas you can cause them to pass out from the pain with a single blow. Considering she has access to the likes of bruce lee's one inch punch and CHUCK NORRIS's roudhouse kicks this would certainly be acheivable.
Another important factor in this fight is her ability to use bullseye's accuracy with thrown weapons. Now from the new avengers arc we know that Maya is astoundingly rich, meaning she could easily get access to vibranium weaponry. With the ability to throw weapons with 100% accuracy every time it would simply be a case of hitting atlas on various key arteries. There is an artery on the inside fo the thigh which if punctured will result in death almost instantly. Literally you will be dead the second you feel any pain, it's that quick. Atlas has increased durability but with vibranium throwing knives she could easily penetrate his skin resulting in a quick death and an easy win.
The final ace up Maya's sleeve (in terms of attacking) is her mastery of the Katana. These blades (if made correctly) have the ability to slice through solid steel. Again atlas's size will give maya ample opportunity to get behind him and hack at the back of his ankles. Why the back of his ankles? Simple really, there is a tendon called the achiles tendon, this allows a person to remain upright, cut it and the will fall to the floor and not be able to get back up again. With as big a target as atlas's ankle she would easily be able to sever this resulting in effective paralysis of her victim and through incapacitation victory is gained.
In terms of defense maya has access to most of daredevils acrobatic skills meaning she would easily be able to avoid anything the slow and lumbering atlas could throw at her while making her way to the necessary areas.
This is an easy victory for echo, which is a shame as I like atlas as a character. But this is a contest and victory trumps all
WINNER:ECHO!