Another win on time

I have only one game left in this round of the tournament, 'cause my opponent let one game tick away. But why the one he could have won, I don't understand. The two games we played are quite the opposite of eachother, in one I'm up material, in the other I was down. My opponent made a move in the former, but not in the latter, so I won this on time. Then I loaded the position to a chess software and finished it against the computer. Well tried at least. With a knight and a couple of pawns down, it is not exactly easy to win a game even if positionally I'm better.
So I still haven't lost a single game in the first round, but it's only because my opponents gave up for unknown reasons.