Ten minutes. This duration of time wasn't short in the slightest for a duel.
In the early days of the Glory Alliance, matches had a time constraint. In those days, a 1v1 match had a five-minute time limit. If there was no winner after five minutes, the winner would be decided on who had more health left.
The time constraint was originally intended to help out the broadcast, but because of this type of rule, a lot of passive strategies were used. For example, after obtaining a certain lead in health, they wouldn't try to fight the opponent and ran around the map instead to play hide and seek.