Sinema built a coalition of independents and moderate republicans. The exit poll for ED voters show she won 10% of voters who approve of Trump. (Despite all this, she didn’t even manage to get a majority, even in a D+9 national environment). Compare this to 2016, with a R+1 Congress. When considering the national margin change from 2016-2018, AZ actually trended Republican LMAO
Also, senate elections don’t always correspond with presidential elections. (Imo, I’m pretty sure Trump will win West Virginia even though Manchin won it in 2018.)
Clearly only Sinema could win AZ...which is why she won it by about the same margin as Dems did in the cumulative House results.