He sought to do no more, but endured Rupert's fiery attack and wily feints in an almost motionless stillness.

Almost, I say; for the slight turns of wrist that seem nothing are everything, and served here to keep his skin whole and his life in him.
There was an instant--Rudolf saw it in his eyes and dwelt on it when he lightly painted the scene for me--when there dawned on Rupert of Hentzau the knowledge that he could not break down his enemy's guard.

Surprise, chagrin, amusement, or something like it, seemed blended in his look.
He could not make out how he was caught and checked in every effort, meeting, it seemed, a barrier of iron impregnable in rest.

His quick brain grasped the lesson in an instant.

If his skill were not the greater, the victory would not be his, for his endurance was the less.
He was younger, and his frame was not so closely knit; pleasure had taken its tithe from him; perhaps a good cause goes for something.