SEATTLE - In the continuing challenge to develop young talent, the thought of pinch-hitting for Michael Saunders never crossed the mind of Seattle manager Don Wakamatsu even with Boston lefty Hideki Okajima on the mound and a trio of right-handed bats on the bench.

The Red Sox may be cursing Saunders for some time to come.

A day after breaking up Jon Lester's no-hit bid with a two-run homer, Saunders came through again Sunday. His two-run single in the eighth inning gave Seattle the lead, Milton Bradley followed with a squeeze bunt to score another run, and the Mariners rallied for a 4-2 win over the Red Sox on Sunday.

Saunders entered the weekend with just four hits all season against left-handed pitching. He got two against Lester, including the go-ahead homer in the sixth inning.

A day later, and with his confidence building, the Mariners young left fielder slashed a 1-2 pitch from Okajima into right field to score Jose Lopez and Justin Smoak, with third-base coach Lee Tinsley chasing Smoak almost to the dirt circle around home plate to get the lead run across.

Saunders is now hitting .309 over his last 19 games.

"We've talked about the necessity for him to face left-handers and continue to play. That's just some more of the investment in his future," Wakamatsu said.

The surprising Seattle rally left the Red Sox wondering how a possible sweep in Seattle became an unlikely split of the four-game series as part of Boston's 10-game West Coast swing.

There were plenty of issues for the Red to Sox ponder aside from Saunders. Okajima had an opportunity to stem Seattle's eighth inning rally if he makes the correct play on Casey Kotchman's sacrifice bunt, instead of hesitating and leaving everyone safe and the bases loaded.

"We always give them the option you know if you're not sure, get an out," Boston manager Terry Francona said. "From there it just, I don't know if he didn't have a handle, it didn't look like there was a lot of urgency. They're trying to give you an out and you'll take it, and a lot of times good things don't happen."

There's also Boston's sputtering offense that scored just four runs in the final three games of the series in Seattle - and without facing Seattle ace Felix Hernandez.

All those factors left the Red Sox quiet and frustrated, and eight games back of the Yankees in the American League East.

"Their pitching is not bad, but we should be able to hit better against them," Boston's David Ortiz said. "We're not facing power pitching. We have the experience and the ability to dominate."

Seattle's rally started innocently enough with singles by Lopez and Smoak. Kotchman's bunt was botched by Okajima and Saunders hit gave Seattle a 3-2 lead.

Bradley, pinch-hitting, followed Saunders with a squeeze bunt for a base hit - done on his own - that scored Kotchman.

"Man on third, no outs, the last thing they probably expected me to do was bunt," Bradley said. "I knew if I put it down there on the right side it was an easy run."

Okajima (3-3) gave up two runs and five hits. One of the runs in the inning was charged to Daniel Bard, who allowed Lopez's single.

Seattle's rally ruined a strong effort by Boston starter Daisuke Matsuzaka, who struggled with major control problems early before settling down to be in line for his third straight win.

Matsuzaka was wild early, at one point in the third inning already over 60 pitches and with an equal number of strikes and balls. But the Japanese righty settled down and retired 10 of the final 11 batters he faced. After Matsuzaka escaped a bases loaded jam in the third, he started rolling, setting down the Mariners in order in the fourth, then allowed one base runner in the fifth that was left at second base.

But his high pitch count early forced Matsuzaka out after six innings and Seattle took advantage of Boston's bullpen. Matsuzaka allowed just one run and four hits, but was hampered by five walks. He struck out four.

"I was just desperate in trying to do what I could to give our team a chance to win," Matsuzaka said.

Chris Seddon worked 2 2-3 perfect innings of relief for Seattle, but it was Brandon League (8-6) getting the win after he struck out Kevin Youkilis for the final out of the eighth inning. David Aardsma pitched the ninth for his 18th save in 22 chances.

Boston's only runs came in the fourth off Seattle starter Doug Fister. Kevin Youkilis doubled to score J.D. Drew and Adrian Beltre singled to score Ortiz. But Boston didn't have a base runner after the fifth.

NOTES: Smoak's single in the eighth was just his third hit of Seattle's seven-game homestand. He was 3-for-28 in the homestand. ... Francona said it's possible injured C Victor Martinez will be activated during the Red Sox upcoming series against the Angels.