"I don't think I've ever seen anything like it, where this many guys have struggled at the same time," Fuentes said.
The new closer, a three-time National League All-Star in Colorado, was referring to the collective woes of an Angels bullpen that has started more fires than it has extinguished.
With six runs in the sixth inning and three more in the seventh, the Halos had carved out a 9-4 lead for starter Jered Weaver, who outdueled Andy Pettitte through six innings after surviving a rocky first.
But the Yankees' offense -- persistent to the finish -- and the Angels' bullpen proved to be a flammable combination.
As a group, Halos relievers are 1-8 with a 7.69 ERA, surrendering 55 earned runs in 22 appearances covering 64 1/3 innings.
"We have to settle down and hold leads," Angels manager Mike Scioscia said. "Until we get settled in the bullpen, that's going to be a challenge for us. We just hope we can keep swinging the bats the way we have. When we get settled [in the bullpen], it's going to translate into wins."
Los Angeles pounded out 13 hits, with Matthews and Erick Aybar delivering three apiece and Mike Napoli reaching base four times (two singles, two walks in his debut as a designated hitter).
Bobby Abreu singled and walked twice, departing with what was described as lower back tightness after stealing his second base of the night -- he's 11-for-11 in thefts -- in the sixth.
Abreu likely will be rested on Saturday when CC Sabathia faces Matt Palmer, making his second start with the Angels and fifth of his career.
Pettitte seemingly had things under control, cruising with a four-run lead, when Los Angeles erupted in the sixth.
Singles by Torii Hunter and Napoli started the inning, but Pettitte was one out away from escaping when Jeff Mathis slashed a two-out bullet through the middle for two runs. Aybar's bad-hop single and a walk by Chone Figgins -- Pettitte's last hitter -- loaded the bases for Matthews.
Mark Melancon started him with a first-pitch fastball, and Matthews sent it rocketing into right-center for a three-run triple.
When a wild pitch on ball four to Abreu brought Matthews home around Melancon's tag, the Angels had their biggest inning of the young season.
They scored three more in the seventh. Napoli walked, and Howard Kendrick lined a single to left. After Maicer Izturis won a long duel with Jose Veras with an RBI single to right, Mathis squeezed home Kendrick with a perfect bunt.
Matthews' sacrifice fly -- sending Melky Cabrera against the wall in right -- made it 9-4.
Safe and secure? Not here.
The Yankees (13-10) began chipping away, first at Rafael Rodriguez and Jose Arredondo with a four-run eighth inning featuring Ramiro Pena's two-run single, and then at Fuentes.
The 6-foot-4 southpaw, reduced almost exclusively to fastballs in search of his elusive command, walked leadoff man Mark Teixeira. Successive singles to Hideki Matsui, Robinson Cano and Posada set off the enduring voice of Sinatra.
Not since 2000, in Chicago against the White Sox, had the Angels (9-13) lost a game when leading by five or more runs after seven innings, according to the Elias Sports Bureau.
"As a whole," Fuentes said, "we're not executing pitches. We're getting behind [in counts]. I don't think anyone down there is happy with the way they're throwing the ball now. I think everybody down there has high expectations.
"Myself, personally, I need to throw strikes, get ahead of guys and then throw my secondary pitches."
Fuentes (0-2) said he was looking to jam Posada with a fastball on the hands with the infield up, hoping for a play at the plate, but the catcher applied solid wood and sent it sailing to left-center.
"I tried to go hard, middle in, and he put a good swing on it," Fuentes said. "He's a good hitter."
Weaver overcame a rough start to go six innings in a superior effort, allowing only two singles -- one on a bunt -- and one walk from the second through the sixth.
"Weav really knuckled down after that first inning when he was a little out of sync," Scioscia said. "Once he got out of the first inning, he made some adjustments and pitched well from innings two through six."
Rodriguez shut down the Yankees in the seventh, but the eighth brought a wall of sound to the Bronx. It stayed very loud until Posada brought the hammer -- and the curtain -- down.