Yet with a 3-2 victory Sunday, Seattle took two of three from Boston, which finished its final West Coast trip of the season 2-4.
From the Red Sox perspective, the outcome is less an encouraging sign for a Mariners team that lost 101 games last season and more about their own recent struggles, which includes the benching of David Ortiz.
"Today was a tough day," Boston manager Terry Francona said. "[But] what happened last week doesn't affect us."
Rocco Baldelli was 0 for 11 with seven strikeouts in three games as the designated hitter for Ortiz. J.D. Drew and Jason Bay were 3 for 11 (.272) with one strikeout and one extra-base hit in the No. 3 spot in the batting order usually held by Ortiz, who is batting .208 with no home runs entering his return Tuesday against Toronto. First baseman Kevin Youkilis becomes eligible to return from the disabled list on Wednesday.
"When you don't have your three and four hitters, that is probably not going to help," Francona said. "I don't know that we sit back and think of it like that -- like, where our offense is."
"I think we are just one or two hits away from doing this," team captain Jason Varitek said. "It is definitely huge [being without Ortiz and Youkilis]. Our team is much better with both of them in the lineup."
Seattle's series win erased the gloom of a 1-7 road trip that ended with two straight losses in the last at-bat at first-place Texas.
"It's about a belief system," rookie manager Don Wakamatsu said. "If we can beat a team like Boston, that's a stepping stone for where we want to go."
Seattle won for just the third time in 13 games because Boston shortstop Nick Green threw what should have been Cedeno's third-out grounder in the ninth about 15 feet over the head of first baseman Jeff Bailey, into a camera well behind first base on the fly. It was generously scored a single and error, Green's second of the game and eighth of the season.
"It just ... happens," Green said. "Obviously it happened at the wrong time. I tried to slow things down. I slowed it down too much. Was lazy."
That wasn't the only wasted opportunity for Boston. Varitek doubled and Green walked with one out in the ninth against David Aardsma (1-1). Jacoby Ellsbury then popped out to the infield and angrily slapped his bat, and reigning AL MVP Dustin Pedroia flied out to keep the game tied.
It was the second time in two outings Aardsma, traded by Boston last winter, had denied Ellsbury and Pedroia in the ninth inning of a Seattle win.
"You don't want to be facing them with the game on the line," he said, grinning over the dual escapes since taking over for Brandon Morrow as Seattle's closer. "Yeah, I'm pretty happy."
Seattle won the series despite starting Chris Jakubauskas, Garrett Olson and Jason Vargas. On offense, Griffey and Beltre were combined 1 for 23 (.043). They stranded four base runners Sunday, and 10 in the series.
Vargas allowed eight hits and one earned run -- Drew's sixth homer in the fourth -- in 5 1/3 innings.
Ellsbury extended his hitting streak to 13 games, the AL's longest active streak. ... Seattle C Rob Johnson left the game after bunting a ball off his hand in the sixth. He has bruised index and middle fingers on his right hand. Though X-rays were negative, he said he may be out a couple days. Kenji Johjima replaced him.