Updated

The Boston Red Sox are starting to cook with gas. At least in the Emerald City that is.

The AL East-leading Red Sox eye a series win over the Seattle Mariners Thursday in the finale of a four-game set at Safeco Field.

Boston lost Monday's opener, 11-4, but recorded 11 runs in each of the next two games. The Red Sox took Tuesday's game by an 11-8 score, then handed the Mariners an 11-4 loss on Wednesday behind another big night from designated hitter David Ortiz. Ortiz went 2-for-3 with a home run and three RBI, and is now the all-time hits leader among designated hitters.

Ortiz needed one hit to pass Harold Baines for the DH mark. He had four hits, one of which was a homer, and three runs scored on Tuesday.

"It's great, man. I mean the fans, they look forward to that," Ortiz said on Boston's website. "They look forward to watching a guy breaking records and getting to certain levels."

Jacoby Ellsbury finished 3-for-4 with an RBI and two runs scored to extend his hit streak to 18 games, while Shane Victorino had two hits and two runs batted in to help the Red Sox win for the 11th time in the last 15 tries. Ellsbury had an 18-game hit streak back in 2011.

Felix Doubront hurled seven innings of one-run ball and struck out six batters for the win (6-3).

The Red Sox are 3 1/2 games ahead of Tampa Bay for the AL East lead and 3-3 on a 10-game western road trip. The trek continues this weekend with three games against the Oakland Athletics.

Ryan Dempster has allowed at least two runs in all but three of his 18 starts for the Red Sox and gets the nod Thursday. He has not received a decision in each of his previous two trips to the mound and allowed three runs -- two earned -- and seven hits in 6 1/3 innings in Saturday's 9-7 loss at Anaheim.

Dempster, a right-hander, is 5-8 with a 4.04 earned run average this season and 1-1 with a 2.16 ERA in four career games (2 starts) against Seattle.

Seattle has lost two in a row since winning five of seven games.

In Wednesday's lopsided loss to the BoSox, Aaron Harang was shelled in the start and he permitted seven runs and eight hits in five innings.

"They made me work," Harang said of the Red Sox. "I was falling behind in the count early on and you can't do that with a lineup like that."

Brendan Ryan hit a solo homer and both Kendrys Morales and Justin Smoak added an RBI double for the Mariners. The Mariners have hit at least one homer in 18 straight games, the longest such stretch since running off 18 straight from Sept. 9-29, 2012.

The Mariners will host the LA Angels for three games this weekend on the homestand and are scheduled to send Erasmo Ramirez to the mound Thursday for his season debut. Ramirez went 1-3 with a 3.36 ERA in 16 games (8 starts) with Seattle last season and posted a 3-3 record with a 3.09 ERA in seven starts at Triple-A Tacoma in 2013.

Ramirez, a right-hander, did not record a decision last June 30 in a 3-2 win over Boston and tossed 2 2/3 scoreless innings. Jeremy Bonderman was supposed to start Thursday for the M's, but Seattle designated him for assignment.

Seattle and Boston are engaged in a series for the first time since the Red Sox took five of nine encounters a season ago.