Sharks prop Andrew Fifita.

Andrew Fifita credited some "old school Tongan treatment" from his father for enabling him to overcome pre-match fears about his knee injury and captain Cronulla to a gutsy 26-22 win over Penrith at Southern Cross Group Stadium.

Just a week after thinking his season was over, Fifita took over the captaincy duties in the wake of injuries to Paul Gallen, Wade Graham and Luke Lewis and the representative prop played a remarkable 73 minutes. He finished with 130 running metres, six offloads and 45 tackles.

However, Fifita revealed afterward that he had been hesitant to play on the morning of the match and needed some "hard love" from his father to convince him he could inspire his team-mates to their first win in four weeks.

"To be honest I was fearing myself this morning," Fifita said. "Honestly, I was that scared to take the field today, just the way I got my knee but I got a little help from my dad. He kind of pushed me over the line on Tuesday night."

Asked what his father had done to help him play, Fifita described a painful massage in which he said, "he just walked all over me".

"It was just that old school Tongan treatment," Fifita said. "It is not the best of treatments, you feel like crying when he does it but it is what it is and that got me playing today."

The former NSW and Australian prop, who has pledged his ongoing commitment to Tonga after last year's World Cup, was also thankful to the Cronulla physiotherapist for helping to get him on the field when he didn't think he would be able to play.

"He worked every day and night, he helped me on my days off and got me ready for a match," Fifita said.

"That was unexpected. Last week I was thinking my season is finished."

Sharks coach Shane Flanagan praised Fifita for the role he played after the Sharks went into the game without Gallen and Graham, and then lost Lewis to a calf strain in the 13th minute.

"Last week, we thought he had done his ACL and his season was over," Flanagan said. "For any player who has been told that, it probably puts a bit of fear into you and then the week that he has had, he hasn't been able to train a lot, but his effort today was outstanding."

After being in doubt with a calf strain sustained the final minutes of last weekend's 40-20 loss to St George Illawarra, Lewis passed a fitness test but injured his other calf in the 13th minute and hobbled to the sideline.

Afterwards, he had his right calf heavily strapped and is in doubt for next Saturday's match against Gold Coast at CBUS Super Stadium.

"We are battered at the moment, with Gal, Wade and Lewie out but I am just proud of the whole group," Flanagan said. "That's the Cronulla Sharks, we know it is there and we will see it more often than not."