Deus vs. Ultimecia

Xenogears vs. Final Fantasy VIII.

Fight 1:
Original Deus vs. Regular Ultimecia.

Fight 2:
Final Form Deus vs. TC Ultimecia (her final form)

Well unless Deus Existed through all time being just as powerful.

Then Ultimecia can just gio aback intime before Deus became all powerfull and kill him.

You seem to forget her time traveling is limited to what the machine can do for her...after that she needs Ellione's help to go further back.
Deus is well over 10,l000 years old...a bit beyond Ultimecia's time travel limit from what we saw.

Someone wasnt paying attention to the game. But I will go bak and play to rechec

Just look at the script. Odine says it himself. Ultimecia can not just go back as far in the past as she wants and alter it. Hell, the only way she can alter time is by taking over the body of another sorceress.