I guess you have a narrow image of how Google look in to the websites when rankings in SERPs against different key phrases. The images should some good measurements but there is nothing that allows me to come up with the answer of domain 1 or domain 2…
We even have no clue how many things Google consider but we at least know that they are 200+ signals.
My advice for whoever domain is losing to analyze every area that may be on-page optimization, content, back links, social, press links or others and if anything is bad or at least not up to the mark then try to fix it and work accordingly.
Hope this helps!