But wait if Daybreaker says that she’s stronger than Nightmare while she’s using nightmare’s magic then isn’t she basically saying “I even use your own magic better than you”

@Pizza Lord  
Agreed, they may seem super god like at first cos they move the sun and moon, but really it’s just because that’s what their special talents were

I still don’t buy into the theory celestia is more powerful. I think they bot have the same power level. but both their powers specialize in different things. Just from watching the show and what happens in it.

@Background Pony #E540  
Yeah I agree, said that in the first comment. It just too Celestia to get the hang of it first.

@Spoonlol  
Luna would be more powerful in the realm of dreams, since her talent seems to related to all things night.

@Pizza Lord  
It somewhat goes into it a little bit into the nightmare Knights and 2018 annual comic. It’s says that there darker forms are a lot more powerful then their ordinary forms. An alternative universe Pony of Shadows tries to change them.
 
In nightmare Knights Daybreaker survives the treatment while Luna doesn’t. Can’t remember if Daybreaker actually defeats Luna in that or if it’s solely Eris.
 
Like I said, think Celestia was originally the stronger of the two but Luna might be stronger by the end of the series.
 
Annoyingly we never really got to see both their full power levels, but I glad we moved away from the idea that alicorns were “goddesses”. Or Uber powerful for that matter

@Spoonlol  
Right…all the while….having “lunas” magic when defeating Daybreaker. So considering that Celestia is holding “Lunas” magic which means “Lunas” powers and abilities. aka would mean “Luna” has the ability to defeat daybreaker. But of course Celestia was holding onto her magic this time.
 
But hey, it’s simple. Luna is not as weak as we think. Besides, Daybreaker isn’t even real in that construct. 83 How did Luna have ALL that power and ability enough to transform herself into Nightmare Moon causing her to have more power from that? In which Celestia could not stop until she used the elements of harmony. Luna is stronger than we think folks. They’re the same power level in the waking world I believe.

In this one shot at the bottom, not really since it was a surprise attack. We also do see Daybreaker beat Nightmare at the end so I would say say she’s more powerful then her.  
But also they are in a dream, so Luna’s magic is probably stronger as that is her domain. Celestia just needed to believe in herself to use it.  
I do still think Celestia is probably original stronger in the waking world but either 1. She’s given up some of her magic to make Cadance, twi and whoever else over the 1000 years alicorn  
2. Her peaceful rein and busy schedule of ruling as meant she’s lost her edge in the magic department

Daybreaker is Starlight’s dream anyway. She is as powerful as Starlight imagines her to be.