This is the best word for it. The man fights every minute of every round, forces his opponent to do the same, and you never know what might happen. Even if he's against a great fighter, it could end very early.
Excruciating. For the poor Filipino boxing fan who can't afford closed circuit cinema tickets or a satellite dish to watch his fight, totally live, and has to watch it on free TV, (undercards starting at 9AM, Sunday morning and main event finishes around 3PM)