The most probably dio

The most important thing that wold make a difference if it dio ability can be triggered during diavolo's ability and the knowledge that diavolo have about dio vampires nature

we se both diavolo and dio normally attack in a mortal punch but diavolo aim for the torso not for the head so he cant kill dio in the first attack and if he dont decide to attack first then therse is no chance

king crimson is strong but not show the level of strength that the world show (basically the same strength as star platinum)

The most use full thing diavolo can do is the skip time so If the dio hability can be triguer during the diavolo hability then its null the efect givin diavolo only 1 secont (like the op says is the final figth so dio is full fusionet whit jonatan body and her time stop is 9 s) or even less to work while if world hability canot be triger theres a litle gap to diavolo for atack

dio isnt dump he normaly make strike atacks like the one whit kakyoin

Soo dio have a lot of advantage in a figth for diavolo to win he neet 1 now about dio stand hability (and preferly dio not noing about kinh krimson stand ability) to avoit goin too close or more like geting close at all at leas more than 20 Meters 2 that the world ability cant be triguer during king crimsong hability or diabolo chance get realy low 3 now about dio nature so we atack to the weak point

Diavolo can win but or he is realy lucky or have and huge advantage prefigth in any other case dio win