Then, in the second, with former A's pitcher Fautino De Los Santos on the mound, Weeks reached base again on a free pass and came around to score on Adam Rosales' double. Rosales crossed home plate soon after, when Seth Smith hit one off the right-field scoreboard for a two-run homer, his first of the spring.
Weeks, Rosales and Smith combined to go 6-for-8 with five RBIs from the top three lineup spots.
But the split-squad Padres didn't go down easily. Facing right-hander Dan Straily, San Diego plated two runs in the first, courtesy of RBI hits from former A's Mark Kotsay and Travis Buck.
Straily, fighting for a rotation spot, lasted 1 1/3 innings in his spring debut, giving up two runs on two hits with one walk and one strikeout while utilizing 34 pitches, 23 of them strikes.
"I had to knock the rust off, that's for sure," Straily said. "Having to wait your turn, it feels like it's been a long two weeks, but it felt really good to get out there and throw some pitches."
The Padres added on two in the third inning against righty Bruce Billings and another two in the sixth, when third baseman Cody Ransom launched a two-run homer to left field off southpaw Justin Thomas to make it 8-6.
Oakland's 2012 first-round Draft pick, Addison Russell, walked to open the bottom of the third and stole second base before scoring on infielder Scott Moore's RBI base hit. Andy Parrino also drove in a run.
Up next: Lefty Brett Anderson, who will likely be named the club's Opening Day starter this week, will make his Cactus League debut on Thursday in Mesa against the Cubs, with first pitch set for 12:05 p.m. PT. Righty Bartolo Colon is also scheduled to pitch in the game, marking his first appearance in a big league contest since Aug. 18, 2012. Four days later, he was suspended for 50 games for violating the league's drug policy.
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.