HARRISBURG, Pa. — The Portland Sea Dogs (79-50) came back from a 4-1 deficit to down the Harrisburg Senators (49-79), 5-4 in the opener of a three-game Eastern League series Tuesday night at Metro Bank Park.

The Sea Dogs clinched a playoff spot in the second inning when New Britain’s loss to Richmond was complete, their eighth playoff berth in franchise history and first since 2008.

Portland climbed its way out of an early deficit and took a 4-4 tie into the top of the eighth inning. Neil Holland was working in his second inning and he retired the first man he faced on a strikeout before facing the reigning Eastern League Player of the Week, Keury De La Cruz. The designated hitter crushed a home run to right on an 0-2 pitch to give Portland a 5-4 lead.

With two outs in the ninth, Harrisburg used a single and a walk against Sea Dogs reliever Pete Ruiz to put the tying run in scoring position. Noe Ramirez relieved and retired Brian Jeroloman to end the game.

The Sea Dogs jumped out to a 1-0 lead in the first as Michael Almanzar picked up an RBI to score Mike Miller off of Senators starting pitcher Austin Voth.

But, Harrisburg put up four runs in the home half of the first as Jason Martinson launched a grand slam home run on a 3-2 pitch from Portland starter Luis Diaz for a 4-1 lead.

The score remained the same until the fourth when Portland tallied two runs to close to 4-3. Carson Blair singled and Stefan Walsh lifted a big fly to right field for a two-run home run.

After Harrisburg reliever Paul Demney worked two scoreless frames, the Sea Dogs tied the game against the righty in the seventh on a solo home run by Blair.

Diaz settled in after the first, going 5.2 innings on six hits, two walks and five strikeouts. Ruiz picked up the win, going two scoreless frames.

Voth lasted just three-plus innings for Harrisburg. He struck out one, walked one and permitted six hits.

Game two of the threegame series is tonight at 7 p.m. Portland sends Justin Haley (0-2) to the hill against Felipe Rivero (1-6).