Cronulla have held off a late comeback from Manly, climbing into the NRL's top four with a 20-14 win.
Earlier Newcastle recorded a much-needed 46-26 win over the Gold Coast Titans.
Shorn of confidence and fluidity for much of the opening hour, Anthony Seibold's Sea Eagles took the game down to the wire with late tries to Reuben Garrick and Lachlan Croker.
But Cronulla held firm, condemning Manly to a third-straight defeat ahead of an unenviable trip to Canberra.
A victory in front of 10,358 fans at Brookvale Oval would have been tough for the Sharks to swallow given how comprehensively they had dealt with Manly's threats.
Sharks halfback Nicho Hynes performed a fine job of marshalling Manly's Tom Trbojevic, whose form has been constantly scrutinised this season.
Trbojevic warmed up to the task on Sunday but still looked short of his best.
NSW State of Origin coach Brad Fittler has backed Trbojevic's form but the superstar fullback is leaving it late to guarantee his selection as a must-pick when the teams for game one are announced next week.
Hynes, by contrast, is making his case for selection all the more irresistible by the week.
He continually kicked Cronulla into good field position in a running battle with Manly and Queensland captain Daly Cherry-Evans.
Cronulla played like a team with a point to prove following their shellacking at the hands of the Dolphins at Magic Round.
Five minutes in and they had Manly behind their posts, after Hynes sent a rampaging Royce Hunt over the top of Haumole Olakau'atu.
Hynes converted Hunt's try, added a penalty, then had a helping hand as Sione Katoa went over in the corner to register his sixth try of the season.
Manly, who had lost prop Josh Aloiai to a shoulder dislocation, added a penalty on the stroke of halftime through Garrick.
The reduction in margin ensured Manly had an avenue back into the game but Cronulla were keen to take that away from them.
Sharks backrower Briton Nikora burst down the right touchline and found a supporting Jesse Ramien on his inside.
The game looked as good as over but led by Cherry-Evans and workmanlike prop Taniela Paseka, the Sea Eagles had a slither of hope.
Garrick touched down in the 63rd minute with hooker Lachlan Croker soon following him over to set up a grandstand finish.
Cherry-Evans kicked a Hail Mary up-and-under as the hooter sounded, but Sharks No. 1 Will Kennedy was able to cling onto the ball and a Cronulla victory.
Knights run up a score against Titans
Five-eighth Kalyn Ponga has bounced back to form and inspired Newcastle to a 46-26 win over Gold Coast that pushes his case for State of Origin selection and silences critics of the Knights' bye-week holiday schedule.
Ponga was completely outgunned in his first full game at No.6 two weeks ago in a performance that raised serious concerns about his ability to compete in the defensive frontline on his shift from fullback.
But while his teammates shipped out to Bali, Fiji, Tasmania and beyond during Newcastle's round-10 break — copping plenty of media criticism — Ponga spent the bye putting in extra work at training to prove he could return to his best after his concussion problems.
The extra reps paid off in a big way at McDonald Jones Stadium, with Ponga enjoying his best game for the Knights in recent memory to help them to a first win since round six.
The Titans had the better of a scrappy opening half but Ponga put the Knights back on level terms at the break when he threaded the ball through the line with a grubber kick for Tyson Frizell in the final seconds of the first half.
He lifted his intensity after the break, first sending former Titan Greg Marzhew over with a cut-out pass and then scything past Tanah Boyd and Jojo Fifita on a line break that set up Bradman Best.
The Best try restored the Knights' lead but Ponga was not yet done.
He burst down the left flank on another line break only three minutes later and then dummied past Jayden Campbell to score a try of his own.
Newcastle were well and truly on the front foot by that point and did not surrender their advantage.
Ponga's performance would not have gone unnoticed by Queensland coach Billy Slater, who is set to choose between incumbent Maroon Ponga and Brisbane star Reece Walsh to fill the fullback spot in Origin 1.
Best shrugged off criticism of his trip to Bali by pouncing on a Titans error in the in-goal to grab a second try in the final five minutes.
Titans second-rower David Fifita was the best of a beaten bunch, scoring two tries to push an Origin case that is fast becoming irresistible.
He crashed past Frizell and Lachie Miller for a try that opened the Titans' account and then gave Gold Coast a late sniff by belting away on a 95-metre line break to clinch a sixth career double.
But it was too late for the Titans, who were left to rue taking poor fifth-tackle options early in the game.
Frizell was placed on report for entering a tackle late to hit Tino Fa'asuamaleaui's legs but appears unlikely to face suspension given Parramatta's Junior Paulo received a fine for a similar offence earlier in the weekend.
Newcastle recruit Adam Elliott made an incident-free return from the groin injury he suffered in round one, making 31 tackles.
