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The Pittsburgh Pirates eye a season-high fifth straight win on Tuesday when they play the first of two games against the Seattle Mariners at Safeco Field.

Pittsburgh continued to roll on Sunday, as Travis Snider's tie-breaking single highlighted a four-run 10th inning and a furious late comeback that gave the Pirates a wild 10-9 victory over the Los Angeles Angels of Anaheim and a three-game series sweep.

The Pirates trailed 6-3 entering their final at-bat, but struck for three runs against Angels closer Ernesto Frieri in the top of the ninth before battering the Anaheim bullpen again in the 10th en route to the franchise's first-ever sweep of an interleague set on the road.

"To finish the way we did, very strong, was a good team victory," said Pirates manager Clint Hurdle. "To sweep a series on the road gives you added confidence."

Third baseman Pedro Alvarez has been a driving force behind the Pirates' recent tear, as he has raised his average 25 points to .237 over the course of an eight-game hitting streak that has included home runs in each of his last four games.

Alvarez, who is trying to become the first Pirates player to homer in five straight games since Jose Castillo from May 26-31, 2006, is second in the majors with nine home runs since June 2.

Hoping to benefit from the red-hot Alvarez will be lefty Jeff Locke, who is 6-1 with a 2.01 ERA. Locke did not get a decision on Wednesday in Cincinnati, but it was through no fault of his own, as he tossed seven scoreless innings in a 2-1 loss.

In fact Locke has allowed just one run in his last three starts, spanning 19 2/3 innings. Over his last nine starts, though, he's only received 2.59 runs of support.

"I know that I've got guys here I got to do my best to take care of, because they're taking care of me," Locke said.

Seattle, meanwhile, will counter with lefty Joe Saunders, who is 5-7 with a 4.48 ERA. He's been solid at home, however, posting a 4-2 mark with a 2.53 ERA in seven starts at Safeco.

Saunders lost in Anaheim on Wednesday, despite a terrific effort that saw him surrender just a run and six hits in eight innings of a 1-0 loss.

He is a perfect 2-0 in three starts versus the Pirates with a 3.15 ERA.

Seattle has won two in a row on the heels of a three-game losing streak and won in thrilling fashion on Sunday, as Kendrys Morales' pinch-hit three-run homer in the bottom of the 10th inning propelled the Mariners past the Oakland Athletics, 6-3.

Raul Ibanez also hit his team-leading 16th and 17th home runs on Sunday, and he has hit 15 of his 17 long balls since May 10.

"It's not something that you think about at all," said the 41-year-old Ibanez regarding his age. "You train in the offseason for however long you've been training and do your thing. The age thing, you don't really think about it."

Seattle split two games with the Pirates in early May at PNC Park.