Sharks winger Jacob Gagan performed strongly for his best game in first grade, scoring two tries.
Penrith's woes were compounded with skipper Peter Wallace to have scans on his right knee on Monday.
The No 7, in his first game back from injury, went from the field midway through the first half. He did return but hobbled through the rest of the match and showed up to the post-match media conference with an ice pack on his leg.
With back-up half Tyrone Peachey also in the casualty ward, the Panthers can ill afford another injured playmaker.
Panthers coach Ivan Cleary said his team were guilty of a lack of urgency and needed to get back into a winning frame of mind.
"It's such a tight comp - it's been like that all year. We've seen enough upsets for everyone to understand that, if you look too far ahead and try to work out who's going to finish where, you might just take your eye off the ball," he said.
"At this point, we've lost two in a row so our next focus is making sure we play well next week."
While 2014 has been tough going for the Sharks, with the ASADA investigation hanging over the club and a seemingly never-ending string of injuries relegating them to the bottom of the table, stand-in captain Wade Graham said he could see positives.
The win over the Panthers was the side's third over a top-eight team in five starts - following on from come-from-behind victories over the Sydney Roosters and Brisbane.
Graham said the team were better than their position on the ladder indicated and were beginning to show their potential with troops coming back.
"For the last month or so, we've had the same team. (Captain Paul Gallen) Gal has been in and out," he said.
"But we've had some consistency with our seven, nine, six and fullback. If you have that, you go a long way to having a cohesive team.
"Throughout that Origin period, we had 14 blokes in rehab, as well as the blokes who played Origin. The competition's too tough to play without quality players."
