The Warriors are ruing lapses in concentration that allowed Manly to recover from 16-0 down to claim a hard-fought 26-22 NRL win in Perth on Saturday.
The Auckland-based side scored three tries in the first 17 minutes, but clocked off through the second quarter to allow the Sea Eagles to draw level by halftime.
A slow start to the second-half allowed Manly to build out to a 10-point lead, before wing Charnze Nicoll-Klokstad's second try gave the Warriors hope through the last quarter, but desperate defence held them out.
Having spoken in the lead-up about the need for his players to be more ruthless, Warriors coach Stephen Kearney was left to reflect on another patchy performance from his side.
"Totally. That's the nature of this competition, you've got to be on your game for the full 80 minutes," said Kearney.
"You can certainly have periods where you're not quite where you [need to be] but you've got to minimise the damage during those periods.
"And we just couldn't do that today against a pretty potent attacking team."
After a blemish-free opening period, the Warriors began to tire through the middle of the ruck and were exposed on the edges as Manly scored three long-range tries.
With captain and Queensland State of Origin hopeful Dally Cherry-Evans pulling the strings, the Warriors were unable to contain the Sea Eagles potent attack.
"We could see they were getting a bit of a roll-on through the middle," said Warriors captain Roger Tuivasa-Sheck.
"We spoke about trying to tighten up and trying to stop them getting that roll-on through the middle, but Manly got momentum and players like Cherry-Evans and Dylan Walker just played on the back of it.
"It was tough for us to defend because we started to clock out, which was a negative for us, and that's why it's so disappointing because we're better than that."
The result continued the Warriors winless run in Western Australia (0-9) but their bad luck began pre-game, with back-rower Ryan Hoffman ruled out with a broken metatarsal in his right foot.
They suffered further blows with prop Albert Vete missing the second-half with a broken arm, before young hooker Nathaniel Roache departed with a hamstring injury.
With first choice No9 Issac Luke already sidelined with a shoulder injury, Kearney will be sweating on the fitness of their forward stocks over next week's bye round before resuming their campaign against Penrith at Mt Smart Stadium on July 14.
The Warriors currently remain in 10th spot on the NRL ladder and four points outside the top eight, with eight games remaining as they look to secure their first finals appearance since 2011.
"What we need to worry about is we've got a few bumps and bruises and making sure that we take stock of that," said Kearney.
"[We need to make sure] that we put our best foot forward towards the back end of the year and that's all our focus is and that's not going to change."