I have a good story about a similar situation...
I was heads up up with an Albanian who spoke fairly good English. I was ahead about 60/40 in a $10 SNG when he asked for a deal, except he wanted 3 more dollars than what was offered to him. I declined, And I ended up beating him in the end.
I guess the point is that if you feel that you have an edge over heads up opposition that asks for a deal, then you should just go for the 1st place prize.
The victory feels alot sweeter.