Seattle, WA (SportsNetwork.com) - Michael Pineda outpitched Felix Hernandez and beat his former club as the New York Yankees chased the Mariners ace and rolled to a 7-2 victory over Seattle on Monday.

Pineda (7-2), dealt from the Mariners to the Yankees in 2012, struck out nine over six-plus innings and scattered two runs, seven hits and two walks.

Hernandez (8-2) was knocked around for seven runs and did not make it out of the fifth. He walked five and allowed six hits, the most damaging a grand slam from Mark Teixeira that gave the Yankees a 7-0 lead.

An expected pitcher's duel started out that way as Pineda and his former teammate matched zeroes through the first three innings.

Hernandez needed just 21 pitches in mowing down the first nine Yankees he faced, but he started becoming unraveled in the fourth, perhaps as a result of a wet mound.

"That's not an excuse," Hernandez said adamantly after the game.

Brett Gardner and Chase Headley both singled to start the frame, and Gardner scored on a wild pitch. Back-to-back walks loaded the bases, and a double-play ball off the bat of Brian McCann made it 2-0.

"I think the first few innings we were probably a little over aggressive and then we made the adjustment," Teixeira said.

Two more walks sandwiched around a single filled the bags again in the fifth. Headley drove in a run with a sacrifice fly, and after Alex Rodriguez singled, Teixeira took Hernandez deep for the ninth grand slam of his career.

Hernandez got the hook following Carlos Beltran's two-out double, and it stayed 7-0 until Pineda finally let up in the seventh.

Seth Smith tripled down the right-field line and scored on Austin Jackson's double, but the Mariners did not muster much offensively against New York's bullpen.

Game Notes

The Yankees had dropped three of four coming in ... The Mariners fell to 1-4 on their 11-game homestand ... The seven earned runs were the most allowed by Hernandez since giving up eight against the Rangers on Aug. 23, 2013. He had pitched to a 1.49 ERA in his previous five starts against the Yankees.