Ryu was given a comfortable early lead to protect, as his teammates scored four runs in the first inning off A's starter Jarrod Parker.
Ryu kept Oakland off the scoreboard until Michael Taylor's home run leading off the fifth inning. It was the only run he allowed on three hits with four strikeouts and a walk.
"I used all of my pitches and built my pitch count up to 69," said Ryu. "Overall, I'm very satisfied with my command, everything was down in the zone."
The A's cut into the lead in the sixth inning when Josh Donaldson slugged a two-run homer off Brandon League. Chris Perez took over and retired the two batters he faced and J.P. Howell picked up the final outs in the seventh inning.
Non-roster catcher Miguel Olivo padded the cushion with a three-run double in the bottom of the seventh inning off Luke Gregerson. Olivo then stole third base and scored on Miguel Rojas' bloop single.
Up next: Further evidence that Dee Gordon is in and Alex Guerrero is out at second base comes Tuesday, when Gordon makes the trip to Surprise to face the Royals and Guerrero does not. For the last few games, Gordon has been starting opposite shortstop Hanley Ramirez, an indication that the staff wants the pair to prepare to play together. Dan Haren starts for the Dodgers.