NSW winger Brett Morris is likely to be available for State of Origin II despite suffering a hamstring injury in St George Illawarra's club-record ninth straight win, a 24-18 victory over Wests Tigers on Sunday.

Morris left the field immediately after scoring a 39th minute try, finishing a 90m effort started by captain Ben Hornby that took the Dragons out to a 20-6 lead.

The Blues winger, one of seven Dragons who backed up from Origin I last Wednesday night, had made a strong comeback from his Suncorp Stadium nightmare where an error cleaning up a kick allowed Queensland winger Jharal Yow Yeh to score a crucial try.

Morris had also played a leading role in Matt Cooper's sixth minute try at WIN Jubilee Oval, beating two players and laying on a deft pass, while he was also disallowed a try in the 34th minute.

Dragons coach Wayne Bennett said early signs were the winger had not torn the muscle.

"He just felt pretty weak on the run and realised it was starting to tighten up," Bennett said.

Morris is likely to miss 1-2 weeks, meaning he will be available for Origin II at ANZ Stadium on June 15 but won't have the opportunity to impress in the Dragons' next outing, against Parramatta on Friday night, before the NSW team is named next weekend.

St George Illawarra hung in for a five-tries-to-three victory, which came after a late Tigers comeback, to better the joint venture club's previous best streak of eight wins in 2005.

The home side led 20-6 at the break before centre Mark Gasnier appeared to have scored the sealer with his 21st try in 15 games against the Tigers in the 61st minute.

But an off day for goalkicker Jamie Soward, who managed just two from four, and a 75th minute try to Tigers back Tim Moltzen, brought to mind the Dragons' second-half fadeout against Canterbury two weeks ago.

They weren't using Origin as an excuse.

"We just focus on whoever's out there has got to do their job whether they're backing up or not," skipper Hornby said.

"Benny Creagh and Beau Scott were out there for nearly the whole game coming off a tough encounter on Wednesday and to be able to stay out there was great for us."

It was an attempted flick pass from Gasnier which allowed Moltzen to capitalise on a Robbie Farah grubber and set up a tense finish, the Tigers unable to come up with the match-winning play.

"We definitely went in there with a plan," Tigers skipper Farah said.

"I thought some of the things we did definitely worked.

"We did lose the game but there's plenty to take out of it."

The Tigers lost fullback Wade McKinnon with a hamstring injury of his own in the warm-up, while winger Matt Utai suffered a suspected broken arm.

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