KANSAS CITY, Mo. -- Danny Valencia, Kyle Seager and Nelson Cruz homered in the first two innings as the Seattle Mariners overpowered the Kansas City Royals 8-7 on Sunday afternoon in the opener of a doubleheader.

The initial three home runs came in the first 13 batters, putting the Mariners up 7-0.

Cruz also homered in the seventh inning and finished the game with 84 RBIs.

Danny Valencia, the second batter of the game, homered after Danny Duffy (7-7) walked Jean Seaura.

Three batters later and with two out in the first, Seager clubbed his 16th home run.

A passed ball on Drew Butera, who is filling in for the injured Salvador Perez, in the second inning led to four unearned runs. Butera's passed ball came on Robinson Cano striking out, which would have been the final out of the inning. Cano reached first and Segura scored on the passed ball.

Cruz then went deep making it 7-0. Cruz's blast in the seventh was an estimated 465 feet.

Duffy lasted 5 2/3 innings, charged with seven runs (four unearned) on seven hits, three of them home runs, and two walks, while striking out eight.

Mariners rookie left-hander Marco Gonzales, who was obtained in a trade last month with St. Louis, retired the first seven batters he faced before giving up a single to Alex Gordon. Two batters later Whit Merrifield homered, his 12th.

Gonzalez did not make it through the fifth. He walked Butera, gave up a single to Merrifield and a run-scoring double to Lorenzo Cain to start the inning and finish his outing.

James Pazos (3-3) replaced Gonzalez and got the victory. Merrifield scored on an Eric Hosmer ground out to Valencia and Melky Cabrera flied out to center fielder Guillermo Heredia to get Cain home.

Mike Moustakas hit a two-run homer, his 31st, in the eighth off Nick Vincent.

Edwin Diaz collected his 23rd save, working around a walk in the ninth.

Mariners right-hander David Phelps left after facing only batter in the seventh. Phelps motioned for the trainer to come out. It was later announced he had elbow discomfort.

NOTES: The Mariners obtained 1B Yonder Alonso, who has 22 home runs and was a 2017 All-Star selection, from the Athletics for minor league OF Boog Powell, who began his career in the Oakland farm system. Alonso is scheduled to join the Mariners on Tuesday in Oakland. ... The Royals put C Salvador Perez on the 10-day disabled list with a right intercostal strain and recalled C Cameron Gallagher from Triple-A Omaha, where he hit .294 in 68 games. ... The Mariners promoted RHP Cody Martin as the designated 26th man for the second game. The Royals' 26th man was RHP Jake Junis, who is scheduled to start the second game. ... The Mariners' Saturday rainout was their first in Kansas City since Aug. 19, 2004. ... Seattle is off Monday before opening a series Tuesday at Oakland. LHP Ariel Miranda will start for the Mariners, while the Athletics will start RHP Kendall Graveman. ... Royals RHP Ian Kennedy and St. Louis RHP Carlos Martinez are the probables Tuesday in Kansas City.