Penrith coach Ivan Cleary has hailed his understrength side’s gallant effort in their 20-16 NRL loss to South Sydney on Sunday.

Missing seven front-line players to injury, the Panthers stunned the defending premiers to take a 12-0 lead inside the opening half hour of the match.

But a hamstring injury to winger Robert Jennings in the first half swung momentum back to the Rabbitohs, who levelled the game by halftime.

Penrith had numerous opportunities to steal the win in a tightly-contested second half but for the second week in a row, Cleary was left to rue a series of crucial errors at critical junctions in the match.

“I thought the effort was really good, but just some big errors,” he said.

“(South Sydney) finished with six extra full sets of six by the end of the game and last week I think it was an extra nine or something.

“The last two games we had every right to be able to get the two points but couldn’t get them.”

After suffering some heavy losses in recent weeks, Cleary said he was pleased to see some of his young talent fight through their growing pains.

“You watch our games at the moment you could say there’s a few rookie errors in there,” he said.

“However I thought today the boys showed a lot of resilience in that sense.

“There were a few games there a few weeks back where the lads dropped their heads a bit.

“Today there was never any sign of that which was great.”

Cleary also questioned why Rabbitohs winger Aaron Gray wasn’t sin-binned for a professional foul for holding back a supporting Will Smith during a line break early in the second half.

“We probably could have got a try early in the second half when Will Smith was held back,” he said.

“I thought I saw a professional foul, I don’t know what you thought.

“I would ask, what is a professional foul? We took the game 40 metres backwards and there was a lot of time spent on that.”