Former NSW State of Origin half Mullen had struggled with what appeared to be a hip injury from the 15th minute and eventually succumbed in the 23rd.

The Knights needed to play the final quarter of the match with just one man on the bench after interchange forward Cameron Ciraldo suffered a bad ankle dislocation.

Representative forward Steve Simpson lasted just 15 minutes before hurting his hamstring.

Mullen is likely to miss 2-3 weeks with a rib injury, while Simpson could be sidelined for a month.

In Mullen's absence, late call-up Scott Dureau stepped up, scoring one try, setting up another and booting a timely 40-20.

The Knights scored four tries to two to open their 2009 account in front of 11,148 fans.

Newcastle coach Brian Smith was focusing on the positives rather than the injuries, rating it the best win since he'd been at the club.

''The way the cards came out in the deal it was us that had the adversity within the game,'' he said after Cronulla's disrupted week following Brett Seymour's two-match ban. ''It was a tremendous, blue-collar, hard-working, just-keep-going [win].''

Smith revealed Dureau had been sent to Shark Park last week to do the Knights' homework on Cronulla.

''He came up with the plan,'' Smith said. ''They tend to respond better when they're hearing it from each other than when they're hearing it from a cranky old coach all the time.''

Cronulla was without injured stars Ben Ross and Brett Kearney, as well as suspended halfback Seymour who took the unusual step of publicly apologising for a drunken night out before kick-off.

Sharks coach Ricky Stuart said the ''disjointed'' week was no excuse.

The Knights led 12-6 at half-time and extended that lead four minutes after the break when interchange forward Chris Houston dived over from dummy half.

They went ahead 24-6 when Dureau set up Richie Fa'aoso in the 47th minute.

The Sharks narrowed the gap when halfback Blake Green scooted over in the 50th minute.

The Sharks were denied twice by video referee Phil Cooley in the first half after five-eighth Trent Barrett had given them an early lead with a try off his own bomb.

Dureau finished a 75m movement to score the Knights' first try before Cory Paterson to score their second off a Junior Sau pass. AAP