The most nervous Jarryd Hayne felt the day of his NFL debut?

When the Australian rugby star was informed during warmups that he would be getting second-team reps at running back for the San Francisco 49ers, behind Carlos Hyde.

"That gave me sort of a shot," Hayne said. "I was like, ‘Whoa, throw me into the deep end.'"

The Aussie did not sink. Rather, he ran. And impressed in the Niners' 23-10 exhibition loss at the Houston Texans.

Hayne, who has been thought of mostly as a practice squad candidate by observers, broke off a 53-yard run up the left sideline in the second quarter after being sprung by big blocks from fullback Bruce Miller and backup left tackle Patrick Miller. He led all rushers in the gme with 63 yards, on five carries.

He also returned two punts for 24 yards and had a kickoff return for 33 yards. In total, Hayne had 120 yards.

"I've watched the physicality of his play in the rugby and he never missed a beat when he put on the shoulder pads," said Niners coach Jim Tomsula. "That was the first hurdle I was concerned about.

"But he can play in space. He's a premier athlete in the world in space."

Hayne getting run with the second-team offense, ahead of Kendall Gaskins and rookie Mike Davis, was somewhat surprising (Reggie Bush did not play and Kendall Hunter did not make the trip).

But a preseason opener, facing players likely sticking on a 53-man roster, is exactly the stage for a player/project like Hayne.

"I didn't get to the end zone, which is obviously disappointing because it's what I was aiming for," he said. "But for me to just get out there and have a solid series, a solid run, that was the biggest thing for me.

"I didn't want to go out there and look like a rugby player; I wanted to look like an American NFL player. And I felt I did that."