Minerva McGonagall
don't stop til you're dead
Nymtheriel
Most people under this circumstance would stumble and perhaps even fall over upon this occurrence; Augusta Longbottom moves at something of a speed.
But if you were to try to rank every wizard in the Isles by combined total athletic ability and combat effectiveness, Minerva McGonagall would probably be in the top ten. Maybe even the top five.(1) She's pivoted smoothly and fallen into step slightly before she even actually consciously registers her old friend as a human person and not an environmental hazard. "I'll have you know," she sniffs, "I'm well above average on this metric for Hogwarts professors."
(1) This depends on weighting, since you have to consider outlier-uneven combinations like Albus Dumbledore, who could outfight any three other people on the planet while standing perfectly stationary but if somehow completely prevented from doing magic would be no more resilient against being punched in the face than any other ninety-year-old man who spends most of his time sitting at desks, or Aidan Lynch, who is astoundingly talented at Quidditch and could probably physically lift and throw a person twice his mass without breaking a sweat but cannot cast a shield charm to literally save his life. But the skillsets overlap nonzero enough that by any reasonably sensible weighting, you'd see a lot of the same names pretty near the top of the list, at least in this decade: Filius Flitwick, Arcturus Black, Septimus Weasley, Peggy Carter (Sr.), Abraxas Malfoy, Antonin Dolohov(2), Peter Pevensie, Bellatrix Black-Lestrange...
(2) Unless of course you have an accurate view of his combat prowess (which most people don't). Antonin Dolohov is an exceptional strategist and not actually a very good duellist. He mostly survives fights by standing behind Abraxas.