Valentine V Jotaro

Location: On a train.

Round 1: Jotaro doesn't have time stop. Valentine is aware of Jotaro.

Round 2: Jotaro has time stop 2 seconds. Valentine isn't aware of it's existence.

Round 3: Jotaro has time stop 5 seconds. Valentine is aware that Jotaro is on the train and that he has 5 second time stop.

Round 1: Valentine wins. His stand is insanely haxxed to the point where it needed a power that perfectly nullified his' to beat him.

Round 2:I'm inclined to give it to Jotaro if he played it smart. In a time stop, he could near instantly kill Valentine, like aiming for his heart or a good old gut punch a la DIO might work. The trick is to incapacitate Valentine. Still, because of them fighting in a train, Valentine still has a decent chance of winning.

Round 3:Valentine wins here, due to him being aware of his timestop. He will most likely try to fight Jotaro in a place where there's space between objects, so he can use his power efficiently.

Also Jotaro can't abuse his timestop like DIO can. Maybe if they weren't in a train, I could see Jotaro winning, but the environment just favors Valentine too much.