St George Illawarra captain Ben Creagh has lashed his team's discipline after conceding nine penalties and having three players on report in an ugly 19-12 defeat of Penrith at WIN Stadium on Thursday night.

Second-rower Tyson Frizell (tripping), centre Euan Aitken (dangerous contact) and forward Jake Marketo (lifting) were all placed on report by referee Ashley Klein and Dragons coach Paul McGregor is resigned to being without Marketo, at least, in the lead-up to the finals.

"It doesn't look great, we will have to review that but I am not sure about Tyson's and I definitely have questions about Euan's as well," McGregor said of Marketo's 48th-minute tackle on Lelani Latu. "Certainly one of them, there was a question mark over. I think we saw where he finished and went off the field so that wasn't good."

Penrith captain Jamie Soward also suggested Aitken would have a case to answer after Tyrone Peachey was left with an injured neck from contact with the St George Illawarra player's knees after he slid into a first-half tackle by Frizell.

"He put his knee on his head, Peachey's neck got bent over onto his chest. It is a dangerous position," Soward said.

The back-to-back penalties against Frizell for a trip on Penrith fullback Will Smith and Aitken helped swing momentum away from the Dragons and they appeared headed for a loss until a 69th-minute field goal by Benji Marshall and try to five-eighth Gareth Widdop six minutes later.

Creagh conceded St George Illawarra had been lucky to escape with a win and said they could not afford to be so ill-disclipined in the finals after losing the penalty count 9-7 and committing nine handling errors.

"That penalty count is not good enough, we are not going to win games with that type of penalty count against quality sides," Creagh said. "We came close to losing tonight and we need to learn to be better than that.

"I thought we started the game really well, I thought the firs 15 or 20 minutes we were in control and then there was a couple of moments there where ... maybe [Marshall] kicking the ball out on the full and a couple of back-to-back penalties, and we were under pressure again. They scored a couple of quick tries and they were back in the game. That is how quickly it turned."

McGregor conceded there were few positives to take out of the match, "besides the fact it is over and we won".

"It was a scratchy win but we have won three out of our last four and we are still alive, and we push that aside now and look forward to the Titans," McGregor said.

"All in all, we play to win and we won but I thought our discipline at times was questionable. We need to fix that up."

After two matches in New Zealand, against the Storm in Napier and Warriors in Wellington, and one in Brisbane in the last month, McGregor said his players would welcome the l10-day turn around until their next game against the Titans on the Gold Coast.

He is hopeful that Joel Thompson will return from a hamstring injury, while Marshall only came from the field in the dying minutes as a precaution.