Nacho,
I don't know the name of the Canadian Camel pilot that Guynemer bested, and I'm not sure anyone does.
However,
Cecil Lewis of No. 56 Squadron had a "demonstration combat" with Guynemer in a SPAD and Lewis in an SE 5. Lewis wrote eloquently about this in
Sagittarius Rising and also in
Farewell to Wings. He says that, "In his hands the Spad was a marvel of flexibility. In the first minute I should have been shot down a dozen times." Lewis was far from a novice himself at this time.
Greg