Jarryd Hayne detailed how he overcame adversity in another eye-catching performance for the San Francisco 49ers in the NFL pre-season.

Hayne delivered a punt return from fellow Australian Tom Hornsey of the Dallas Cowboys 27 yards in the first quarter of their 23-6 win, and finished with eight rush attempts for 54 yards - including a 34-yard run.

The former rugby league star said his over-the-shoulder catch and punt return just three minutes in came despite him battling vision issues - another step in the right direction for the 27-year-old, who is vying for a spot on the 49ers' roster.

"When I was getting out there, I was putting my helmet on and... I must have smudged the screen, so I was looking for a towel, I needed to wipe it because I couldn't see," Hayne told a news conference.

"And my head's everywhere, and soon as the ball went up, I lost it straight away and as a punt returner you need to get the read as early as you can, and I've lost the ball - I couldn't even see it. 

"And then, by the height, the way it was kind of rotating, I knew it was long and I just thought to myself, 'Gee, that's going a long way'. I just turned back and took off, and was getting the read on the way down. 

"I literally just put my hands out and hoped it'd land in my hands, I actually thought it was going to roll off backwards. 

"He [Hornsey] hit it sweet - there's not too many balls I've seen kicked like that, where the ball's been hit sweet. The rotation of the ball was crazy."

San Francisco's defence stood up on Sunday, allowing just the lone touchdown in the final quarter - and Hayne said the improvement in their special teams' unit was there for all to see.

"The key thing for us when we get out there, we've got to read fronts they have, who we think is coming, and our reads can go from a linebacker, to a safety, to a corner," the former New South Wales State of Origin representative said. 

"We've gotta look out for a lot of people, and so defences like to move around and confuse us as well. 

"The little things, with times and games, you get used to. 

"Returning the football, our returning scheme, where we want to take the ball, we think we can attack the defence. 

"From a special teams' [perspective], from where we started to where we are now, it's come along in leaps and bounds."