Opponents were batting .293 against Angels relievers, and the bullpen had suffered four defeats when the Angels led after seven innings.
But on Tuesday, for at least a night, everything fell back into place.
After a shaky Palmer left with no outs one batter into the sixth frame, Jason Bulger pitched a scoreless sixth and seventh, striking out three, veteran setup man Scot Shields tossed a spotless eighth and closer Brian Fuentes slammed the door shut in the ninth, striking out the side for his 10th save.
"We have a lot of talent and a lot of depth in our bullpen," said Shields, who still has a 7.36 ERA. "That was a bad stretch we went through, and I take most of the blame for it.
"But it seems like we're getting in sync."
Fuentes, whose ERA was lowered to 4.61, agreed.
"That's how you draw it up, but sometimes it doesn't always work like that," he said. "But it's always been good by us. We're always very confident in our bullpen. We always remained optimistic that whoever we send out there will get the job done."
The success of the relievers has come at a good time, with starters John Lackey and Ervin Santana healthy again, slugger Vladimir Guerrero on schedule to rejoin the team on Monday, and starter Kelvim Escobar possibly set to be added to the rotation when his disabled list time is up on June 3.
In the meantime, Palmer continues to add to his mind-boggling early-season story.
The 30-year-old journeyman wasn't lights-out on Tuesday, often looking shaky through five innings in which he gave up five runs on seven hits, including home runs by Ken Griffey Jr. and Ronny Cedeno, but he stayed in the game long enough to qualify for the win and go 5-0 to start his career.
Palmer joins Jered Weaver, who won his first seven career starts in 2006, and Bo Belinsky, who started his career 5-0 in 1962, as the only Angels pitchers to pull off the feat.
"Matt wasn't as crisp as we've seen," Angels manager Mike Scioscia said, "but when push came to shove, he made good pitches.
"He pitched well enough to stay around long enough to win and he keeps staying on that roll."
Palmer was helped out by the Angels' bats, too.
The offense pounded out 14 hits and chased Seattle ace Felix Hernandez after 5 2/3 innings.
The top four hitters in the lineup -- Chone Figgins, Maicer Izturis, Bobby Abreu and Torii Hunter -- combined to go 10-for-18 with three RBIs, with Abreu and Izturis notching three hits apiece.
The Angels also stole five bases and were caught stealing three times in a veritable baserunning free-for-all against Hernandez, relievers Sean White, Mark Lowe and Miguel Batista and Seattle catcher Kenji Johjima.
"We were running a lot and we created some runs, and we also ran into a couple of outs," Scioscia said.
And finally, the Angels' bullpen worked out just as Scioscia and his staff drew it up out of Spring Training.
For a team that has won four of the last five American League West titles largely because of the success of its relief pitching, Tuesday signaled a long-awaited return to form.
"It's a good feeling," Bulger said. "We haven't been throwing the way we want to or the way we know we can, and we've taken that to heart. The results are starting to show.
"We've had confidence in each other all along, and we knew we would turn things around sooner or later. We don't take that lightly."