A Luke Keary masterclass has propelled the Sydney Roosters to a dominant 26-18 win over the Sea Eagles to kick-start their NRL premiership defence.

With Cooper Cronk (hamstring) and Jake Friend (shoulder) missing, the reigning premiers shuffled the decks with Keary shifting to halfback and Latrell Mitchell to five-eighth, only for those plans to fall through when Brett Morris was helped off at halftime with a suspected knee injury.

The changes mattered little as the new-look halves pairing tore the hosts to shreds in a first-half blitz at Lottoland that saw the visitors open up an unassailable 22-0 lead at the break.

State of Origin talk may be premature but Keary must be in contention for the NSW No.6 jersey after he set up all four first-half tries in a performance that was every bit as dominant as last year's grand final display.

Last year's Clive Churchill Medallist was on from the outset on Saturday night as he set up Morris and Daniel Tupou for tries before he poked his nose through the line and popped an offload in traffic to send Boyd Cordner over to make it 16-0.

Having failed to make an impact in the round one loss to South Sydney, fullback James Tedesco roared back into form as he shot through late in the half before Keary found Tupou with a pin-point kick to cap a faultless 40 minutes.

The fill-in halfback was forced off early in the second half but was able to return as his side swept past a Sea Eagles team that looked set to concede a cricket score when Cordner shrugged off a high shot to score off debutant Lachlan Lam's grubber.

The Eagles crowd of 9664 was rewarded for braving monsoonal conditions in the first half when Manase Fainu crashed over in the 58th minute, and there was a glimmer of a comeback when workhorse Jake Trbojevic backed up a break to score in the following set.

The clock proved the hosts' biggest enemy, although they had the last laugh when Reuben Garrick and Daly Cherry-Evans combined down the right edge, before Moses Suli pounced onto a charged-down kick to cut the margin to eight.