As a newly fit Metcalf sat unused on the interchange bench, halves duo Tanah Boyd and Chanel Harris-Tavita gave the Warriors a 16-6 half-time lead in Parramatta on Saturday.
Boyd helped the Warriors draw level at 6-6 with a beautiful short pass for Leka Halasima on the right side, before Chanel Harris-Tavita put Alofiana Khan-Pereira over for his first of two tries on the left.
Harris-Tavita double-pumped to help Roger Tuivasa-Sheck score late, officially sealing a game that had been in the balance until the final 10 minutes.
The Warriors will finish the weekend in the top four and have now won all six games when Boyd and Harris-Tavita have started in the halves this season.
A halves dilemma loomed given the return of Metcalf, who holds a longer contract than both Boyd and Harris-Tavita and was a front-runner for last year's Dally M Medal before injury struck.
But as long as the Warriors keep winning, Boyd and Harris-Tavita will keep starting.
"I'm not making any changes to them. They deserve to stay there and they've done a good job," coach Webster said.
"We're just picking the team on form. Luke's done nothing wrong. He's a good player and if the opportunity comes, he'll take it. But right now this is the best thing for the team."
The Eels lost yet another player in hooker Ryley Smith (sternum) early on Saturday night but continue to hold the gloves amid their injury crisis.
"It adds another layer of challenge to it, that's for sure," said coach Jason Ryles.
Five-eighth Ronald Volkman staked his claim to keep prized recruit Jonah Pezet out of the team, scoring two tries in a standout individual performance.
"Ronny's been great, he's been very consistent with this effort, especially defensively, which is something that he's not known for," said Ryles.
Hours after Pezet returned from his hamstring injury via NSW Cup, Volkman gave the Eels a surprise 6-0 lead dummying past Boyd and Halasima for first points.
With 20 minutes to play, he put Parramatta within four points by grabbing a Mitch Moses kick that Adam Pompey fumbled.
Ryles said he would "wait and see" who would start at five-eighth against North Queensland next week.
"We'll have a look at the tape again and we'll sort of review it from there and see what the best combination and best fit is going forward," he said.
But the Eels fell away late, having fallen off the pace in the second half last week as well.
Minutes after Volkman's second try, Erin Clark put in-form Jackson Ford through a gaping hole in the Eels' middle, before Alofiana Khan-Pereira completed his double by intercepting a Moses pass deep in Eels territory.
"I don't think the scoreline reflected the fight and the effort that we displayed tonight," Ryles said.
"(But) a lot of our fundamental errors, and I'm not saying just with the ball, but escort penalties, kick pressure penalties, sort of hurt us."
