I had the exact same thing happen to me except I was the one following. 
The other guy was attacking a base in a 110 and I was in a Ki-84 I think. 
He went vertical and I followed him up, as he made his turn and came back down I plastered his left engine. After a chase across the base and a few more pop shots at him from 1k out he ran into the mountain trying to go over it. 
so I get a PM.. 
from  oDallaso:  You got no game noob  
 Now keep in mind this was after he had already HO'ed me while I was chasing one of his buddies. 
 
 These guys that get pissed off and have to send PM's crak me up.