I think the answer is no, but just wanted to double check

I’m on a (pre Dec 30) TP run - DUB-LHR-JFK-PHX-PSP. First 3 flights all ok, but stuck in PHX currently. Going to arrive in PSP at least 3, possibly 4, hours late.

Could I claim EU261 (assuming not weather/ATC) as it originated in EU? Or because the only delayed flight is within US, it’s a no? Assume the latter but the former would make this long day a bit sweeter!

Thanks!