"That's pretty cool," said Lopez, who would have preferred three home runs. "I was looking for one pitch to hit hard ... looking for a base hit."
Yuniesky Betancourt contributed two sac flies as the Mariners tied the club and Major League record of five sacrifice flies in one game.
"I didn't know that, my God," Mariners manager John McLaren said after the game. "We talked about this in Spring Training. We talked about anything but a double play. Just get the run in.
"That's really cool. I'm proud of these guys. We're making some headway here."
The Mariners, ignoring the cold conditions, showed patience and intelligence at the plate. They hit behind runners, stole bases, sacrificed and took pitches.
"We just didn't do it one way; we did a lot of little things," McLaren said.
The Mariners scored in each of the first five innings. Their leadoff hitters went 6-for-8 in the game with four doubles and six runs scored. The 11 runs are a season high.
Lopez drove in four runs while Betancourt had three RBIs.
Miguel Batista (1-2), who led the staff last season with 16 victories, finally earned his first one this season. He struggled in his five innings, allowing four runs and seven hits, but the offense bailed him out.
"I had a little bit of a dead arm," Batista said. "It's not a big deal. It's going to happen to me now and then."
Batista said a back injury in Spring Training prevented him from his usual exercise routines between starts.
"When you stop your exercise routines," he said, "your arm weakens."
He added that his back feels better now and expects to settle back into his old ways of preparing for starts.
Royals starter John Bale (0-3) was pressed his entire three-plus-innings outing. The Mariners rapped seven hits and scored five runs off him.
Ichiro Suzuki opened the Mariners' first with a double to right, then stole third. It extended his hitting streak against the Royals to 26 games, dating back to April 14, 2005. He scored on Lopez's first sac fly.
Seattle then scored two in the second, one in the third, two in the fourth, four in the fifth and one in the seventh.
The big blow in the fifth was Kenji Johjima's bases-loaded, two-run double into the left-field corner. It was Johjima's 1,500th career hit. It was his 294th hit with the Mariners added to his 1,206 in Japan.
"I'm finally getting to a number where I can compare with my teammates," said Johjima, who started the season on a 2-for-25 slide but is now hitting .220. "It's actually not quite there yet. We're still working on that right now."
The most encouraging element for the Mariners to come out of the game is the return of veteran lefty Arthur Rhodes. It was his first big league appearance since Sept. 9, 2006. He worked in the ninth.
Rhodes had made the club out of Spring Training a year ago but never appeared. He had damaged ligaments in his left elbow and needed Tommy John elbow ligament replacement surgery.
The surgery took place on May 2. It generally takes 12 to 14 months to recover from it.
"I'm a hard worker. I can come back before that," Rhodes said. "I beat it. I'm proud of myself. I've worked hard.
"I was excited and [had] just a little bit of butterflies. After the first pitch, I felt good. I wanted to just keep the ball down and in the strike zone."
He threw 11 pitches, eight for strikes. He retired one batter, but gave up two singles before leaving. Mark Lowe finished the game by inducing a double play.
This day also carried more significance for Rhodes. A year ago, he wanted to be on the active roster and wear No. 42 in honor of Jackie Robinson. He finally got his chance Tuesday, wearing No. 42 on the day of his return, the day baseball honors Robinson for breaking the color barrier in 1947.
"Today was special, coming back from Tommy John [surgery], getting into the game wearing No. 42," Rhodes said. "I had Jackie Robinson on my mind. I had the surgery on my mind. There were a lot of things going on today.
"Jackie Robinson went out there and played the game hard. That's what I wanted, go out there and do what he did."
The Mariners (7-8) now play five straight games against their AL West rivals on the road, two in Oakland beginning Wednesday night then three at the Los Angeles Angels starting on Friday.