I'm very inclined to say that with similar strength and durability, with both having pointed weaponry means that whoever is able to strike first with their sword is likely going to snowball into a win.
Semblance spam is not the norm for Winter. In her fight against Qrow she only proceeded to use it after an extended period of simply swordplay, so it's unreasonable to assume she's going to use it to summon supposedly 8-B Grimm behind Polnareff.
It is also not the norm for Polnareff to instantly go for the kill unless he is angry, due to his chivalrous nature though. He toyed around a fuckton with Avdol, even when under DIO's control.
Due to inconclusive specifics, it is probably best to assume that Silver Chariot is only 2x as strong as Winter, because both only have rough estimates based on scaling to others. They are both roughly the same speed, even when using their respective speed amps.
So who is going to get that sweet, sweet first blow?
Polnareff has a stand that is 2x as strong and invisible to Winter. You cannot react to what you can't see, it would take an unprecedented stretch of the imagination to assume that from the sensation of touch alone she would proceed to counter all of Silver Chariot's blows with her aura enfused sword.
But, it is unlikely he will go for any lethal blow in his first few attacks. He would definitely be willing to harm her greatly, but I have my doubts that he will go for the head. Therefore I think Polnareff will get the first combo of attacks, but will stop short of immediately killing such a "pretty lady".
This is likely going to warrant Winter to use her semblance to summon a bunch of birds to attack Polnareff from behind. He has demonstrated the ability to withstand a casual blow and being ragdolled by DIO, so I have my doubts that they will do any significant damage. Regardless, they will be a distraction. This is an opening for Winter to strike him down, that's her only option.
I don't think it is enough of an opening to knock him out and prevent him from using Silver Chariot. Pissed off and enranged from an attack, Silver Chariot proceeds to launch a flurry of blows just before she is able to touch Polnareff, this time not holding back. Winter's aura is very quickly depleted by the barrage of sword slices causing her to jump backwards with the aid of her semblance. Unfortunately, Polnareff can shoot his sword, which travels through the air and plants itself straight into her skull. Even if she dodges it by coincidence, the amount of ricochet he has demonstrated is borderline impossible meaning it is not unlikely for him to expect that and have it still follow her anyway.
With that, I believe that is how their abilities would generally interact with one another. I am standing firm on my vote for Polnareff.
For the record, I believe that Winter would have had a much better chance if she could see Silver Chariot, and probably take the win.