SAN DIEGO -- Interim manager Pat Murphy was asked the key question Wednesday afternoon after the San Diego Padres' back-to-back shutout losses to the Seattle Mariners at Petco Park.

Was that good pitching by the Mariners or ineptitude on the part of Padres hitters?

"A combination," Murphy said. "Give them credit, but we have work to do."

A lot of work.

Less than day after Mariners rookie left-hander Mike Montgomery threw a complete-game, one-hit shutout, right-handed starter Taijuan Walker and four relievers blanked the Padres on three hits.

Meanwhile, Mariners second baseman Robinson Cano was 4-for-5 with a home run, a bases-loaded single and a double for three RBIs. Seattle right fielder Nelson Cruz added a two-run homer, his 20th home run of the season.

During the course of two games, the Mariners outscored the Padres 12-0, outhit them 16-3 and clearly out-pitched them. And Seattle played better defense.

Walker (7-6) allowed a hit and a hit batter in six innings en route to his fifth straight win in as many starts. He struck out seven and threw only 76 pitches.

In his past five starts, Walker has allowed six runs, 28 hits and two walks with 36 strikeouts in 32 1/3 innings for a 1.67 ERA.

Walker was a little surprised that he was pulled for a pinch hitter with Seattle leading 1-0 and a runner on with two outs in the sixth.

"But we had the opportunity to score with this being at a National League park," Walker said. "So we'll take all the runs we can get and we ended up scoring there. I thought it was a great team win. The offense did great and the bullpen came in and shut the door."

Seattle manager Lloyd McClendon had no reservations about pulling Walker when he did.

"This is a young pitcher that's going deep into a lot of ballgames," McClendon said. "At some point you have to protect him. He might not like it, but 12 years from now, when he's still pitching, he'll thank me. He'll say 'the old man knew what he was doing.'"

The Padres had only four hits and 10 base runners while being shut out in the last 21 innings to fall to 5-9 under Murphy. Two of the hits were doubles by third baseman Yangervis Solarte, who had the lone hit Tuesday night against Montgomery.

The Padres have been shut out 13 times this season. The 2014 Padres, the least offensive team in the major leagues, were shut out only 19 times. The franchise record for shutouts in a season is 23.

Cano drove in the Mariners' first two runs and Seattle added five runs in the last two innings.

Cano broke up the scoreless tie with his fifth homer of the season leading off the sixth. Cano drove a 1-2 pitch from Padres starter James Shields 387 feet the opposite way into the left field stands.

An inning later, Cano made it 2-0 with a bases-loaded, two-out single to center off Padres left-handed reliever Frank Garces after Shields walked the bases loaded.

Shields, who has been the losing pitcher in his last three starts after starting the season 7-0, allowed two runs, four hits and four walks with seven strikeouts in 6 2/3 innings.

Both Walker and Shields, who lost a third straight decision after starting the season 7-0, opened the game with three perfect innings.

Shields weathered the first storm.

Seattle first baseman Logan Morrison opened the fourth with a single behind second, just beating the throw of shortstop Alexi Amarista to first. Cano followed with a line single to center that barely cleared leaping, 5-foot-6 Amarista, putting Mariners at first and third.

After right fielder Nelson Cruz tapped back to the mound, allowing Cano to reach second (Morrison held at third), Shields walked third baseman Kyle Seager to load the bases with one out. But Shields followed with strikeouts of left fielder Franklin Gutierrez and Jackson.

Walker hit catcher Derek Norris with one out in the bottom of the fourth to give the Padres their first base runner. Yonder Alonso followed with a single to right center to put Padres on first and second with one out. But Walker retired left fielder Justin Upton on a pop fly and Solarte on a deep liner to Jackson in center.

The fourth was the lone inning in the first six that the Padres put a runner on base against Walker, who departed for a pinch hitter in the top of the seventh.

Cano, who had four hits, would have done more damage if Padres center fielder Will Venable hadn't thrown out pinch-hitter Dustin Ackley after shortstop Brad Miller scored on Cano's seventh-inning single.

Cruz singled to open the eighth and moved to third on Seager's double to right. He scored on Jackson's one-out sacrifice fly to Matt Kemp in right.

A sacrifice fly by Morrison opened the Mariners' scoring in the ninth. Cano followed his his run-scoring double and Cruz closed it out with his homer to left off Padres right-handed reliever Marcos Mateo.

NOTES: Mariners LHP Mike Montgomery's complete-game shutout of the Padres Tuesday night was the Mariners' major league-record 35th shutout in interleague play. The Yankees are second with 27. ... Padres 3B Will Middlebrooks still wasn't able to start on his sore ankle Wednesday but was available to pinch hit. ... Padres RHP Brandon Morrow threw a bullpen Wednesday. He is two more bullpens and a simulated game from going on a second rehab assignment.