The Sea Eagles disposed of the Warriors 32-12 in the face of a heavy injury toll on Saturday night. Here are the five key points from the contest at Mount Smart Stadium.
Shaun Johnson's season over
As he stepped through for a classic Shaun Johnson try on 26 minutes, the Warriors playmaker suffered an injury which will ensure he takes no further part in this Telstra Premiership campaign.
In falling over the line Johnson's ankle became trapped under the would-be Manly tacklers behind him, and the look on his face was one of agony straight away.
He was taken straight to hospital and shortly after the final whistle his coach Andrew McFadden confirmed the news no Warriors fan wanted to hear.
"I can't confirm anything but yeah it's season-ending," McFadden said.
"We have got a fair few young guys out there and it was always going to be a challenge [without Johnson].
"Losing Shaun was a blow but we should have been better I feel."
Manly coach Geoff Toovey said the loss of the 2014 Golden Boot winner was a tipping point in the match.
"Massive, I think it was a big loss for them," the Sea Eagles mentor said.
"Like anything if you lose any key playmaker in your team, he was a big loss for them."
Manly do it with 13 for last quarter
In a week in which the NRL announced a reduction in the number of interchanges for next year, Manly showed they can get the job done regardless of how few they are presented with.
After losing Steve Matai, Luke Burgess and Ligi Sao to game-ending injuries in the first half, the Sea Eagles also lost Tom Symonds in the 53rd minute and never got him back.
That left Toovey with no choice but to play the same 13 for the final 28 minutes, as his side stood up despite the obvious threat of fatigue.
"It was a fantastic effort, very heroic from the players in the end there," Toovey said.
"We just ran out of players. Rarely it happens when you lose four players in a game, but it was a physical game and they lost a couple of players as well.
"That's how tought it was."
Captain Jamie Lyon said it made the victory all the more pleasing.
"We knew we were a couple of troops down so we had to dig in," Lyon said.
"I thought the boys were great and we showed a lot of spirit.
"We knew it was going to be tough."
As for updates on the injured men, Toovey confirmed the Sea Eagles could be looking at serious knee injuries for Sao, Symonds and Burgess, with the latter telling NRL.com that he may have have suffered a torn ACL.
Manly still believe finals in reach
After managing just five wins from their first 15 games this year Manly somehow head into Round 21 still in contention for the finals.
The win in Auckland lifts the Sea Eagles to 18 competition points, just four off the pace of eighth position.
But their run home isn't an easy one, with four of their remaining six games against top eight sides in the Broncos (1st), Rabbitohs (4th), Roosters (3rd) and Sharks (8th).
"We believe we do [still have a chance to make the finals]. It's going to be tough, we know that we put ourselves in this position," Toovey said.
"But we have got a pretty tough team and some tough individuals, collectively I think we showed tonight we were a pretty tough team."
Great end to a tough week for the Sea Eagles
The Sea Eagles arrived in Auckland with scandal weighing heavily on their minds this week, following reports their coach and several senior players were being pushed out for 2016.
But the response was typical of the culture at Manly, coming together to produce a convincing upset win despite the off-field circumstances.
"I think they [off-field issues] affect everyone, but it sort of galvanises the players at Manly," Toovey said.
"I think today's repsonse was a good message for everyone.
"To be honest with you I don't want to get into that today. I don't want to take the gloss off the win tonight.
"I thought that all the praise should go to the players."
The club also had only four days to prepare for the match after losing to the Cowboys on Monday night, and did so with halfback Daly Cherry-Evans in significant doubt up until Friday.
"He was in doubt right up until yesterday, he had a fitness test at the captain's run," Toovey added.
"In the position we are in he wanted to play no matter what."
A night of horrors on many levels for Warriors
For a second week in a row the Warriors suffered a loss by 20 points or more, and against the Sea Eagles were leaky on defence and clumsy on attack.
The Kiwi side – who only two rounds ago boasted the best attacking record in the competition – have now managed just two tries in their last 160 minutes of football, while conceeding 56 points.
"Yeah there hasn't been many worse than that for all counts," McFadden said of his side's night at Mount Smart Stadium.
"Obviously a disappointing result and scoreline, and with what happened during the game as well hurt us.
"Probably our young guys, maybe they did just go into their shell a bit.
"Maybe it was just too much tonight.
"But we are not going to throw everything out the door, we will regroup and learn from that.
"The opportunity is still the same for us."