While technically neither won the fight, it was very clear that the Doctor has the upper hand the entire time. Jenny was mind controlled by a telepath, but the creativity parts of her brain were still functioning, so she was at full capacity. The Doctor goes as far as to say he's holding back while still getting the better of the fight, and Jenny begs him to end it as it shows her face and body in clear distress from the Doctor's assault.
Beyond that, Jenny notoriously has one of the more glaring weaknesses for an otherwise legit Trans-level character. That being telepathy. So the Doctor has an easy win there.
No, this was once she was her older, teenage self. If we want to be technical, it was against Habib, not the OP's Jeroen. There's a chance Jenny could exploit some psychological weakness in Jeroen via his drug addiction (depending on what arc it is, and how clean he is at the time) but that's getting pretty speculative. But the power set is the same for Habib/Jeroen, as is the knowledge base.
There is a case to be made for Jenny, involving the near-collapse of reality in the arc with Jenny's evil twin. But I prefer less ambiguous feats, which a head-to-head battle with them both letting loose certainly is.
Where did part of her leg and her one hand disappear to?
__________________ Chicken Boo, what's the matter with you? You don't act like the other chickens do. You wear a disguise to look like human guys, but you're not a man you're a Chicken Boo.