Kat-trick beats Dogs: Katoa flies in for three as Sharks win nail-biter

"He's just such a great kid, Sione. He's worked so hard on his game," Morris said.

"I see that at training all the time, he's got beautiful hands. It just comes natural to him.

"In wet and greasy conditions, to pick that up off his bootlaces like that [for his second try], it was a real big play for us."

Sharks halves Chad Townsend and Shaun Johnson combined well, recording two try assists apiece. Townsend hadn't registered a try assist this season beforehand.

Morris said he was never worried about the No.7's form.

"[Townsend] does so much in and around our team off the ball, setting up our shapes," Morris said.

"He's also got one of the most skilful back-rowers in the game playing outside him, and a lot of our attack does come off Wade Graham."

Matt Moylan started at fullback for Cronulla in his return from a hamstring complaint but switched with Josh Dugan to defend at left centre midway through the second half while roving in attack.

Moylan was forced from the field for a HIA with 18 minutes remaining after being crunched by Dallin Watene-Zelezniak. He passed the test and returned for the closing stages.

"It's important to note, that was only the fourth or fifth time that [Moylan] has played with Wade, Shaun and Chad over the last 18 months," Morris said.

"That's quite bizarre. So it's really good for me that he's pulled up okay and he sort of had a bit of a hybrid role ... That was just a way of easing him into it."

For the Bulldogs, the new scrum-base duo of Brandon Wakeham and Kieran Foran showed promise.

Cronulla opened the scoring spectacularly in the 11th minute with an acrobatic put-down by Katoa. He launched for the line after a looping pass from Townsend.

Canterbury levelled the scores in the 27th minute after fullback Will Hopoate sliced through from a Wakeham short ball, the space created thanks to the drifting Josh Jackson's defender-sucking decoy run.

Sharks back-rower Briton Nikora paid the price for his team's repeated infringements when he was sin-binned five minutes from the break. The Dogs nearly snatched a half-time lead, but Foran couldn't handle an offload with the line open as rain fell.

More Katoa magic pushed Cronulla back in front eight minutes into the second stanza. Running at full speed, the flanker did exceptionally well to collect a low Johnson pass.

Wakeham was sin-binned and placed on report for belting a defenceless Dugan as he was being dragged towards the touchline.

The Sharks immediately took advantage of the extra number with Johnson kicking beautifully for Katoa to score his third.

Canterbury responded when lock Adam Elliott, not renowned for his kicking skills, placed a grubber into the in-goal and Foran won the race.

Watene-Zelezniak - who played in the centres - produced a bell-ringer on Moylan that rocked the stadium. With Moylan sent for a HIA, Cronulla opted to keep Dugan at fullback and push usual prop Siosifa Talakai to left centre in defence.

Veteran Bryson Goodwin – who joined Cronulla earlier in the week after being released by South Sydney – scored a crucial try when he latched onto a pinpoint Townsend kick. Goodwin began his career with the Sharks in 2007.

Canterbury's Jake Averillo had seemingly set up a grandstand finish when he picked up a loose ball and raced away, but the Bunker found an accidental offside that denied the points.

Crichton intercepted a Johnson pass moments later, scoring a long-range try, but Cronulla were able to hold on.

"Heart in mouth type stuff, that last few minutes ... We just couldn't afford to walk out of here without the two points in our back pocket," Morris said.