Strange tourney situation with 8 people sitting out

[chessmaster]

I played today a freeroll where all qualified people were preregistered by the site. so i ended at a table where 8 people were sitting out, and effectively played heads up against another guy where every pot was juiced up with the blinds. The bad things were i also was half an hour late, so he already collected about 4000 in blinds and i was almost always OOP as i sat right to him.
I minraised about top 60% of my hands (which gave him still way too many free blinds, but at least he didnt call/reraise me too much), and tried to steal some pots when there was a flop, but it didnt work out too well.
I ended committing my stack with my overpair against a flush draw which hit and i was out, which felt quite silly.
It seems to me he can be very agressive in this situation (which he actually wasnt) since i always lose not only my stack but also all the dead money around when i bust.
I felt completely clueless in this situation, so any advice is appreciated.