Lomax has been the talk of the NRL this season, his highly publicised release request at complete odds with his scintillating form on a move from centre to the wing.
But Lomax, who led the Dally M Medal leaderboard ahead of round eight, had an afternoon to forget in the 23rd annual Anzac Day Cup, just as NSW selection conversations are truly clicking into gear.
With the scores locked up 6-6, the Dragons' best player this season threw a careless offload to Ben Hunt while they were working their way out of trouble.
Hunt, clearly not expecting Lomax's pass, spilt the ball into the hands of Michael Jennings, who passed on to Angus Crichton for the Roosters' second try.
The blemish proved a game-defining moment, swinging all momentum to the Roosters following a tight, physical start to the game.
Easts ran in three more first-half tries and cruised to a 30-6 lead they never looked like surrendering.
"We didn't start too bad and then we tried to make some stuff, a pass from Zac and they scored," said Dragons coach Shane Flanagan.
"Then they scored quickly again and all of a sudden from a good start, leading 6-0 and even 6-all, we were competing well.
"Then they got possession and (were) rolling up the field, getting repeat sets and they were coming off the back fence. We couldn't handle them.
"We came down to earth with a thud."
Even with left-winger Daniel Tupou out and Jennings' mid-game injury forcing more reshuffling, the Dragons could not unlock Lomax, their strike weapon on the right side this season.
He was well contained by opposite man Joseph-Aukuso Suaalii, the Wallaby-in-waiting helping drive Lomax towards the sideline as the Dragons looked to strike back at 12-6 down.
On that occasion, Lomax threw another errant pass that ended the attacking raid.
By the time Lomax injected himself into the attack it was too late, his cut-out pass to try-scorer Tom Eisenhuth reducing the deficit to 48-16 as the final 10 minutes approached.
His running was down, though still better than the rest of the Dragons' best five at 140 metres for the game.
The final try of the game came as Suaalii burst through Lomax in a one-on-one contest.
The Dragons' season at large has followed a similar pattern, with inconsistency just as much a defining factor as improvement.
Flanagan's side came into Thursday's game on the back of consecutive wins, but have now conceded the biggest Anzac Day loss since the traditional clash's inception in 2002 and will finish the weekend outside the top eight.
"They're all terribly disappointed because it is a big occasion," Flanagan said of the loss.
"(The Roosters) did a really good job and we were poor. No excuses."
