Penrith has allayed concerns about its form with a hard-fought 16-10 defeat of fast-finishing South Sydney, but may have cause for concern after Nathan Cleary tweaked his ankle and limped through the second half.

The NRL is also set to investigate claims star Souths fullback Latrell Mitchell was the victim of racial abuse from the crowd at the Penrith home game as he left the field for half-time.

The Panthers felt the absence of departed premiership-winners Viliame Kikau and Api Koroisau in their shock season-opening loss to Brisbane but Cleary’s boot re-energised their attack and had them back in the winner’s circle on Thursday night.

The scoreline did not do justice to a contest dominated by the Panthers, but which was almost snatched by the Rabbitohs and their chief architect Mitchell.

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After coming off second-best in a tackle with Alex Johnston, Cleary opted not to kick for goal when an Izack Tago try extended the Panthers’ lead to 8-0 before the break. He managed to play the game out, albeit with ankle strapping and a limp.

The ankle complaint came at the end of a dominant 40 minutes for the Panthers, who could have been up by more than 10-0 at half-time had recruit Luke Garner not been denied two tries and Isaah Yeo one.

Cleary terrorised the back three with his high kicks, especially inexperienced winger Izaac Thompson, and got the result he was after in the third minute.

The ball bounced in the red zone and travelled through hands to Stephen Crichton to score on the Panthers’ right edge.

The Rabbitohs did well to rebuff the Penrith juggernaut as it rolled forward and looked set to go into the break trailing by only four points.

That was until Jarome Luai broke free down the left side and managed to kick for the speedy Tago even as he was tackled.

South Sydney was slow to come out of half-time and, having been battered through the middle the whole first half, appeared too tired to mount a comeback when Panthers winger Brian To’o sailed over on the right side in the 52nd minute.

However Mitchell’s ball-playing down the left gave the Rabbitohs a sniff, pulling the scoreline back to 16-10 with a try by Isaiah Tass in the final two minutes.

But Souths had left their run too late as Penrith held on for a vital win.

-AAP