On Friday, the Mariners found this out the hard way, falling to the Rangers, 2-0, in 12 innings before 34,055 at Safeco Field.
More than three hours into a tight battle with Texas that featured stellar pitching -- including the long-awaited Seattle debut of former Cy Young Award winner Cliff Lee -- and defense, a few costly miscues undid the Mariners.
Rangers shortstop Elvis Andrus led off the 12th inning with an infield single against reliever Brandon League, who was working his third inning. The next batter, Michael Young, legged out an infield single and watched as Mariners shortstop Matt Tuiasosopo threw the ball past first baseman Casey Kotchman for an error that allowed Andrus to take third and Young to reach second.
League then uncorked a wild pitch, pushing Andrus across home for the game's first run, and two batters later, Julio Borbon knocked in Young for the two-run cushion.
Rangers closer Neftali Feliz pitched a perfect bottom of the 12th for the save and the Mariners fell below the .500 mark at 11-12.
"Offensively, we were pretty anemic," Mariners manager Don Wakamatsu said. "We had two opportunities with the bases loaded, had a chance to win the ballgame pretty easily twice and couldn't do it."
The first opportunity came in the bottom of the 10th, when the Mariners had the bases loaded with one out, but pinch-hitter Mike Sweeney, who batted for starting shortstop Jack Wilson, grounded into an inning-ending double play.
The second one came in the last half of the 11th, when Seattle had runners on second and third with none out. Batter Eric Byrnes set up to try a squeeze bunt and Ichiro Suzuki left from third. But Byrnes pulled back the bunt and catcher Matt Treanor bobbled the ball for a second before recovering in time to tag out Ichiro at the plate.
Then, with the bases loaded and two outs, Byrnes struck out looking at a Frank Francisco fastball.
When asked if he had discussed the play with Byrnes, who rode his beach cruiser bicycle out of the clubhouse and into the stadium tunnel before speaking to reporters, Wakamatsu shook his head.
"We'll discuss that tomorrow," Wakamatsu said. "I don't know what happened."
One good thing that happened to the Mariners was Lee.
The one-month-delayed home lid-lifter for the prized lefty starter the Mariners traded three prospects for over the winter was everything it was billed to be.
Lee, who missed the first month of the season because of a lower abdominal strain suffered during Spring Training, was fantastic, pitching seven shutout innings, not walking a batter, striking out eight, giving up only three singles and throwing 73 of his 98 pitches for strikes.
"It was exciting," Lee said. "I had fun. It's nice to go out there and do your job effectively and give the team a chance. Any time you do that, you've got to be happy. But being the first time for the Mariners and the first time at home, I couldn't have been any more excited about getting out there and getting it behind me. For it to go as well as it did, I'm pretty excited and pretty happy about it."
Unfortunately for the Mariners, Rangers starter Colby Lewis was just as good, going nine innings and giving up three hits while striking out 10.
With a quick turnaround to a Saturday game that starts at 12:10 p.m. PT, catcher Adam Moore said the Mariners won't have too much time to think about Friday's missed chances and the fact that the offense still hasn't gotten into a sustained groove in the early part of the season.
"It's easy to sit here and say, 'Yeah, we're pressing,' but we go out there and compete every day and play the game," Moore said.
"And we try to slow it down as much as we can, and we weren't able to get a run across in key situations tonight," he continued. "That's baseball. We've got to come out here tomorrow with our heads up and come out and swing the bats."
Doug Miller is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.