Jarryd Hayne has continued an amazing start to his NFL career, producing big runs at punt returner and running back in his second preseason game for the San Francisco 49ers.

The former NRL star Hayne made headlines around the world after his 53-yard run in the 49ers' first preseason game against Houston last week as he tries to make the cut for San Francisco's final 53-man roster.

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On Monday (AEST), San Francisco faced the team's old rivals, the Dallas Cowboys at their home stadium in Santa Clara.

Early in the first quarter, Hayne fielded a punt from Dallas, going back 15 yards to catch the ball over his shoulder before turning and weaving his way through the Cowboys' defence for a 27-yard gain to San Francisco's 47-yard line.

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Hayne's big run gave his team great field position and set up a go-ahead field goal for the 49ers to take a 3-0 lead.

Jarryd Hayne does it again for the 49ers: Hayne averaged 28 yards per punt return in opening quarter

Hayne averaged 28 yards per punt return in opening quarter His shortest punt return of 23 yards equalled the 49ers longest in 2014

His shortest punt return of 23 yards equalled the 49ers longest in 2014 Hayne was used as a running back in the second half

Hayne was used as a running back in the second half He was given the ball on five straight carries at one point

He was given the ball on five straight carries at one point He finished with a game-best 54 yards on eight carries

He finished with a game-best 54 yards on eight carries He was used on kickoff coverage in the fourth quarter

Later in the same quarter, Dallas was forced to punt again, and this time Hayne ran the ball back 34 yards before making a wrong turn and being tackled by the Cowboys' last line of defence, their punter, Chris Jones.

Hayne continued to make tacklers miss, with his third punt return going for 23 yards to the Dallas 38-yard line, which set up another Niners field goal for a 6-0 lead.

In his opening three punt returns, Hayne averaged 28 yards a return. Last season the San Francisco 49ers averaged 11.2 yards a punt return.

The league leaders on punt returns were the Houston Texans, who averaged 12.4 yards a return.

Hayne makes another big gain at running back

Hayne was used as a running back in the second half. His first carry, on 2nd down and two from the San Francisco 24 yard-line, made one yard - not enough for a first down.

San Francisco then tested Hayne in earnest, with five consecutive running plays called where the Australian racked up a total of 44 yards.

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The highlight in the series was a run where he burst into a hole and broke free down the left sideline before being tackled for a gain of 34 yards.

The run set up another field goal to make the score 16-0 to San Francisco.

Hayne later made a small loss on a running play, but it was overruled by a penalty against Dallas for a defender grabbing the Australian's facemask to drag him down.

Another Australian, Tom Hornsey, continued his campaign for a spot on the Cowboys' roster as a punter, making a number of punts in the same game.

One of his punts from the Dallas endzone in the fourth quarter was blocked and recovered for a 49ers touchdown, which made the score 23-0.

Hayne added another position to his NFL resume, playing on kickoff coverage for the 49ers.

He was first to get to the returner downfield, and although the Dallas player got loose, Hayne slowed him down enough for team-mates to complete the tackle.

The Cowboys scored a late consolation touchdown to make the final score 23-6.

Hayne finished as the game's leading rusher with 54 yards on eight carries.

Carlos Hyde, who is expected to be San Francisco's number one running back in the regular season, finished with 39 yards on seven carries.

The 49ers have two more preseason games at Denver and at home to San Diego, before the team's opening match of the season in week one, at home to the Minnesota Vikings on Tuesday September 15 (AEST).

All NFL clubs must reduce their rosters to 75 players by September 2 (AEST) prior to the final preseason games.

The clubs must then make further cuts to get the roster down to 53 by September 6 (AEST).

More to follow.