"We're down because we're playing bad baseball," Angels manager Mike Scioscia said. "It's tough to swallow, because we're a better team than that. We're not doing a lot of things right on the field right now. Consequently, we've been looking up on the wrong end of these scores these last four games."

Pennington's homer, which gave Oakland a 10-2 lead, was the 10th allowed by Los Angeles pitchers during the first five games. The Angels, coming off a 10-1 loss to Minnesota on Thursday, are 1-4 for the first time since 1988. The club hasn't opened 1-5 since its inaugural 1961 season, when manager Bill Rigney's squad lost eight in a row after winning the opener.

"We're getting beat in every aspect of the game, from baserunning to defense to what we're doing on the mound and in the batter's box," said Scioscia, last season's AL Manager of the Year. "It's frustrating, but we have a lot of confidence in our club. The strength of this club is that we've got a lot of gamers in that room. So we've got to get back to grinding it out."

On the other side, Oakland is 4-1 for the first time since 2004.

"We have a lot of confidence in our team and in each other," Barton said. "We're taking advantage when there's guys on base and we're getting big hits with guys in scoring position."

Gio Gonzalez (1-0) allowed two runs and six hits over six-plus innings in his season debut for the A's, striking out six and walking one.

The left-hander, who began each of the previous two seasons at Triple-A before getting called up to the big club, got the chance to start this year on the 25-man roster because of an impressive spring training and an injury to Trevor Cahill.

Matt Palmer (0-1) was charged with seven runs -- five earned -- and eight hits over five-plus innings in a spot start for Scott Kazmir, whose spring training was interrupted because of hamstring and shoulder injuries.

It was a profoundly somber anniversary for the Angels, one year after promising young pitcher Nick Adenhart was killed in a car accident.

Adenhart, only 22, had just thrown six scoreless innings against the A's in a no-decision at Angel Stadium with his father watching from the stands. He went out to celebrate his best big league outing but was killed in an early morning crash that also took the lives of his friends Henry Pearson and Courtney Stewart, and seriously injured former Cal State Fullerton catcher and infielder Jon Wilhite.

Oakland catcher Kurt Suzuki, a teammate of Wilhite's at Cal State Fullerton who helped raise funds for his friend's rehabilitation, had an RBI single to help the A's win their fourth in a row following an opening night loss at home to Seattle.

Jered Weaver was presented with the inaugural Nick Adenhart Award in a pregame ceremony. It will be given annually to the Angels' most successful pitcher of the season, as voted on by his teammates. Weaver was the winning pitcher in the Angels' first game after Adenhart's death.

"To be the first recipient of it is an honor," Weaver said. "He was a great person, and there's no better name to go on an award like this. Obviously, it's an award we wish we didn't have to pass out. It was a tough thing for our whole organization and our fans to go through. There hasn't been a day that's gone by where we haven't thought about Nick and wished he was still here with us."

Hideki Matsui, back in the DH slot for the Angels after playing left field for the first time since June 2008, drove Gonzalez's first pitch of the second inning for his second homer this season and 600th RBI in the majors. The eight-year veteran drove in 889 runs during 10 seasons in Japan with the Yomiuri Giants.

Game notes
Angels RHP Bobby Cassevah made his big league debut after getting promoted from Triple-A, allowing only a broken-bat single over the final 2 1/3 innings. ... Kazmir pitched 6 1/3 innings in a tuneup with Triple-A Salt Lake, allowing three runs and eight hits while striking out six. He is expected to return to the rotation next week at Yankee Stadium.