SEATTLE (AP) — Mariners manager Scott Servais had an idea his struggling team was poised for a big performance.

“The guys weren’t real happy with how we played this last couple of days,” Servais said after Seattle’s 8-2 win Wednesday over the Kansas City Royals. “You could feel it in the clubhouse when you came in this morning and we responded.”

Domingo Santana hit two home runs in a game for the third time this season, Marco Gonzales won his third straight start and the Mariners avoided an embarrassing series sweep by returning to a recipe that helped them start the season 13-2.

“Marco pitching well and we’re hitting homers — that’s a good formula for us,” Servais said.

Santana, who had five RBIs, and Daniel Vogelbach hit back-to-back homers in the first inning to give the Mariners a 4-0 lead and they went on to snap Kansas City’s three-game winning streak. The Mariners had been outscored 15-4 by the Royals in the first two games of a series between last-place teams.

Seattle jumped on starter Brad Keller (3-9) immediately. Mallex Smith doubled to open the bottom of the first and J.P. Crawford walked before Santana hit his first home run of the day to left-center field. Vogelbach followed with his 18th of the season, off the Hit It Here Café in the second deck.

It was the eighth time this year the Mariners, second in the majors in homers, have gone back-to-back.

“When these guys make mistakes, you’ve got to make them pay,” Vogelbach said. “You can’t really give them more pitches and more opportunities. Credit to Mallex and J.P. for getting things going, and Domingo hitting the homer. (Keller) made a mistake with two strikes and I was able to make him pay.”

It marked the first time the Mariners scored in the first inning since June 6 and the first time they posted multiple runs to begin a game since May 11. They are 22-12 when scoring first.

Gonzales said he went back to the mound in the second inning riding “a wave of confidence.”

Seattle showed some of the small-ball potential of its new young lineup in the fourth after Dylan Moore singled to start the inning. Keller hit Smith with a pitch, then gave up run-scoring singles to Crawford and Santana before Vogelbach’s sacrifice fly made it 7-1.

Keller didn’t return for the fifth after giving up nine hits and throwing 97 pitches.

“It just felt like I really didn’t have anything behind the fastball today,” Keller said. “It’s kind of not a good feeling when you’re going into a start with that, so I was just trying to create stuff and threw myself out of . whack and left a few balls over the middle of the plate that they took advantage of. Whenever it felt like I didn’t have my fastball, I was trying to manipulate and it wasn’t working.”

Santana added a solo home run, his 15th of the season, in the sixth and finished with three hits. The top three batters in the order — Smith, Crawford and Santana — each scored two runs.

Gonzales (8-6) scattered six hits over 6 2/3 innings, striking out five. It was his third straight victory after going 0-6 in his previous seven outings.

“I think something that’s overlooked with me is my ability to adapt and adjust, and hopefully the past couple of starts have kind of shown that I can bring a different thing every game,” Gonzales said.

HERNANDEZ RESULTS

An MRI showed nothing out of the ordinary in RHP Felix Hernandez’s injured shoulder, Servais said. The 2010 AL Cy Young Award winner is expected to begin working out again soon. Servais said Hernandez could pick up a ball in a few days for light tossing. Hernandez left a minor league appearance Friday night after experiencing fatigue in his shoulder and strained lat. He’ll throw bullpens before making another minor league start.

TRAINER’S ROOM

Royals: SS Adalberto Mondesi was out of the lineup with tightness in his right groin. He’s day to day.

Mariners: RHP Sam Tuivailala threw 30 pitches Tuesday in his first bullpen since taking a step back in his return from Achilles tendon surgery. The reliever said he didn’t feel any of the muscle tightness in his arm that sidetracked his return last month. Tuivailala will report to Class A Everett where he will work out of the bullpen for three or more games until he earns a move to Triple-A Tacoma, Servais said.

UP NEXT

Royals: RHP Glenn Sparkman (1-3, 4.01 ERA) will face the Twins on Thursday night for the second time this week after giving up five runs and five hits in five innings of a loss last Saturday.

Mariners: Servais said he will likely use an opener Thursday and then turn to Wade LeBlanc (3-2, 6.20 ERA) in the series opener against Baltimore.