"On Sunday [when he struck out four Royals in two hitless innings, walking one], that was as good as I've felt in a long time. I had good movement and was hitting both sides of the plate.
"I brought basically the same stuff out there [Tuesday night]. One thing that was different was a couple of fastballs got away from me. But the two pitches they hit were breaking balls."
J.D. Drew opened the ninth by stroking two-strike curveball into left-center for a single. Catcher Jeff Mathis, Shields said, was going down to block it, indicating how far Drew had to reach to make contact.
Shields had picked up in the eighth for Jose Arredondo, getting the final two outs of the inning as the Red Sox scored twice to draw even. With Drew on and one out, Jason Varitek was presented a gift from Shields in the form of a 1-2 curveball that flattened out and fell right in his wheelhouse.
The veteran catcher raked it to right-center for the RBI double that Jonathan Papelbon protected for his ninth save.
"I missed with an inside fastball and then I threw what might have been the worst pitch of my career," Shields said. "I tried to bury a breaking ball ... and didn't."
In the wake of the loss, Angels manager Mike Scioscia said he thought Shields had thrown well other than hanging the breaking ball to Varitek.
"Scotty's stuff was fine," Scioscia said. "I think he's excited about where he is now."
Shields was philosophical about absorbing a loss with quality stuff, recalling a game in April against the Red Sox that had a different outcome.
"I walked three guys -- I was all over the place -- and got out of it," he said of that 5-4 April 12 victory by the Angels, Shields holding the lead and Brian Fuentes registering the save.
Shields, who has led the American League in holds with 31 for three consecutive seasons, feels the bullpen is rounding into form, Tuesday night's blip notwithstanding.
"Brian is throwing well, and everything is falling into place," Shields said. "The guy who hasn't had any luck is Jose Arredondo. He's been throwing great. He just hasn't had any breaks. It's good getting Darren Oliver back [from a triceps strain]. He really stabilizes things for us."
It will take a month or so of quality work for the back-end guys -- Shields (7.82), Arredondo (6.43) and Fuentes (5.40) -- to shave their ERAs down to respectable numbers.
Overall, the Angels' bullpen is last in the Majors in ERA at 6.90 and has a 2-9 record with five blown saves.
"We'll be fine," Shields said, undaunted. "I feel good about our 'pen, I really do."
So does the big man in the dugout.
"The arms are there," Scioscia said. "It's taken a while -- a long while -- and things aren't quite settled yet. But our confidence is there."