It's not like the A's scaled Mount Everest on Sunday with a 6-3 win over the Los Angeles Angels.

Kilimanjaro, maybe.

Since the start of the 2011 season, Angels starter Jered Weaver had been as tough as anyone in baseball on the A's, going 8-1 with a 0.87 ERA.

This time around, the A's rocked him for four runs in the third inning and didn't let up the pressure, providing more than enough offense for starter Sonny Gray as Oakland completed a sweep of the three-game series.

Did the A's, who have won five of their first six against the Angels this year, mess with the Angels' minds? It was more like the two-time defending American League West champs certified their authenticity.

"It's important for the team to gain confidence," shortstop Jed Lowrie said. He homered and singled and drove in two runs. "Beyond that, as for sending a message, I don't know. I'm too focused on the day-to-day grind of things to analyze that."

Third baseman Josh Donaldson drove in seven runs in the series, two of them with a bases-loaded single in the third inning that broke Weaver's stranglehold on the Oakland offense. Donaldson said the sweep in which Oakland outscored the Angels 26-11 would speak for itself without the A's resorting to playing mind games.

"We played well this series," he said. "We got some timely hits. We pitched well. I think it's just one of those things. We walk out of here feeling good about ourselves."

And how should other teams feel about the A's, now an American League-best 35-22 and 4½ games up on the Angels in the A.L. West?

"Hopefully they'll take us for granted," Donaldson said with a big smile. "Our whole thing is trying to take it one game at a time."

It seems that's wishful thinking on Donaldson's part. Weaver made it clear that any team that underestimates the A's is likely to have egg on its face when the day is done.