Dosu was uncomfortable when Neji got angry and had his Byakugan active, ready to fight. Neji was also portrayed as stronger so... Imo Neji takes this rather quickly. His byakugan will allow perception on Dosu's abilities and in CQC Dosu is toasted.
The one Gaara killed before the final round of the Chunin exams.
Oro/Kabuto pretty much sent Dosu to his death. R.I.P dosu T_T , people even forget who he was :'(