SEATTLE -- Still trying to find their way to .500 six weeks into the season, the Seattle Mariners already have three certainties among their five-man rotation.
Felix Hernandez. Hisashi Iwakuma. And Joe Saunders at Safeco Field.
The veteran left-hander continued his inexplicable dominance at the Mariners' home stadium Sunday, allowing just one run over 6 1/3 innings to beat the Oakland A's 6-1.
Saunders is now 3-0 at Safeco Field this season, with an ERA of 0.94. The 31-year-old southpaw, who has never lost at Safeco in 13 career starts, is 0-4 with a 12.54 ERA in four road starts this season.
Kendrys Morales and Jason Bay both provided homers for the Mariners, who have not lost a series since the Houston Astros beat them two of three from April 22-24.
The A's (19-20) finished off a nightmare of a road trip in which they went 3-7. Oakland scored more than three runs in only two of those games.
Morales got hit a three-run homer in the bottom of the first, giving the Mariners a 3-0 lead.
The A's looked as if they would get it all back in the top of the second, which they opened with three consecutive hits. Back-to-back doubles by Josh Donaldson and Luke Montz cut the Seattle lead to 3-1, and a Derek Norris single put runners on the corners with no outs.
However, a key defensive play by Mariners shortstop Brendan Ryan helped end the threat. Ryan scooped up a Nate Freiman ground ball and threw to catcher Jesus Montero, who tagged Montz for the first out of the inning. Saunders retired the final two batters to maintain the two-run lead.
Jesus Montero's RBI single in the fourth gave Seattle a 4-1 lead, and the Mariners added another run after two infield hits and a sacrifice fly in the fifth.
Bay, using a pink bat to commemorate Mother's Day, added a solo home run with a shot to center field in the seventh to put Seattle ahead 6-1.
By that time, Saunders' day was already over. Saunders allowed five hits and three walks while striking out six. He struck out Oakland's Michael Taylor to open the seventh, then gave up a single to Adam Rosales before manager Eric Wedge came to the mound and took him out after 104 pitches.
Saunders appeared mad at himself for giving up the Rosales single, but the fans at Safeco Field gave him an ovation as he headed toward the dugout. Saunders touched the bill of his cap, then went into the dugout and watched Seattle's bullpen finish what he started.
In games started by Saunders at home, or by Hernandez and Iwakuma in any venue, Seattle is 14-6 this season. In all other games, the Mariners are 4-14.
Seattle is unbeaten in its past five series, four series wins plus a two-game split at Pittsburgh. The hot stretch follows a span in which the Mariners lost or split their first seven series of the season.
Seattle is the first AL West team to beat Oakland in a series. The A's are 14-5 against division foes this season.
NOTES: Mariners manager Eric Wedge said before the game that RHP Stephen Pryor, the team's setup man to open the season, is "still a ways away" while recovering from a torn lat muscle. Pryor went on the 15-day DL on April 15. ... Morales' first-inning homer was his first home run since April 23. He now has four on the season. ... Oakland's Brandon Moss struck out on all four of his at-bats.