A frustrated Paul McGregor laid the blame for St George Illawarra’s 18-12 defeat by Cronulla with his players and not the match officials after a controversial refereeing decision enabled the Sharks to make a late escape.

Bronson Xerri was awarded a 76th-minute try but Cronulla teammate Wade Graham later admitted it should have been disallowed as he touched the ball before the teenage centre caught it in an offside position.

The decision ended hopes of a Dragons comeback after fighting back from 12-0 down midway through the first half but McGregor said his players were their own worst enemies as they committed 17 errors.

He was disappointed with the kicking games of playmakers Gareth Widdop, Corey Norman and Ben Hunt before the halfback became one of three St George Illawarra players ruled out of the match with concussion in the 44th minute.

"I am obviously frustrated about the result when we could have done a little bit more ourselves to get the win and not rely on a decision from the referee," McGregor said.

"Our commitment and our effort was certainly there but some of the fundamental errors … there is no excuse for it."

McGregor said St George Illawarra’s goal-line defence had been very good and noted that two of Cronulla’s tries had come from kicks and the third was scored on the last tackle.

"The last one, it comes to the bounce of a ball and OK, Wade touched it, which is good that he is being honest about it, but make it stop. That is the most obvious thing that has got to improve," McGregor said.

"We had 45% possession, and that’s back on us. The finish to our sets weren’t anywhere near where they need to be with the type of players we had on the field today so that needs to improve as well.

"To be in the fight again until the last four minutes is a credit for how well they are doing things for one another but there are a lot of other things we need to get better."

Hunt and Tyson Frizell are expected to be cleared to play against Sydney Roosters next Saturday night but second-rower Patrick Kaufusi is in doubt after being forced from the field with a concussion before half-time.

The loss of the trio meant McGregor had to use three of his eight interchanges on replacing players who failed HIA tests.

The controversial defeat leaves the Dragons in 14th position on the Telstra Premiership ladder, despite the team now being close to full strength following the return of captain Gareth Widdop four weeks ago.

"I think we showed today in patches and over the last three or four weeks that we can beat anyone but we have just got to clean up a few things and quickly," McGregor said.

"It was the same story against Parramatta, if we had executed better we could have won that game. Against Souths, we lost in the last 15 seconds because we didn’t clean up that kick-off, we won last week [against Gold Coast] and we could have won today."