Pineiro (8-5) dominated the Padres from the start, retiring the first three batters he faced.
He retired 20 others, as well, but he hasn't recorded a one-two-three first inning in any of his previous 15 starts.
In fact, opponents have scored 13 runs in the first inning against the 24-year-old right-hander.
Pineiro continued his success, not allowing a hit until the fourth inning. He left the game with a 6-2 lead in the eight to the increasingly familiar sounds of a sell-out Safeco Field recognizing a job well done.
Nelson exorcized a recent demon by inducing a game-ending ground out from Padres outfielder Rondell White. White made a loser out of Nelson with a walk-off grand slam one-week prior.
The offense had plenty to do with victory as well, collecting eight runs and 10 hits to go with eight walks.
Five of those runs came off Snohomish High graduate Adam Eaton (2-7).
Eaton held the Mariners scoreless through three innings, before walks and shoddy defense took its toll.
Eaton walked John Olerud and Mike Cameron to load the bases. Randy Winn hit a grounder to first baseman Ryan Klesko scoring Edgar Martinez. But shortstop Donaldo Mendez couldn't handle Klesko's throw to second, allowing Olerud to score and Cameron to go to third.
Eaton, making his first start in Safeco Field, couldn't escape the fifth, though, as Martinez added to his mark as the all-time RBI leader in Mariner history with an RBI grounder, and Olerud picked up his 37th RBI with a two-out single.
Another Mendez error led to more Mariners' scoring in the seventh. Mendez allowed Cameron to reach first base on a routine ground ball, and Cirillo singled him home for his second RBI of the game (just his sixth multi-RBI game of the year).
Carlos Guillen wrapped up the scoring with his third home run leading off the eighth.
The Mariners scored runs in every inning from the fourth on, but they could have stopped after the fifth with the way Pineiro pitched.
Pineiro has a 4-1 record in his last six starts, losing only a 3-1 decision to the Montreal Expos. He has lowered his ERA to 3.67 – the fourth such top-15 ERA among Mariner starters.
Pineiro also ranks in the top-10 in strikeouts (76), innings pitched (108) and batting average against (.234).
He has at least two starts left before the All-Star break to improve those numbers and his chances of making his first All-Star team.
James is a senior at Central Washington University who will be interning for InsidethePark.com this summer. He welcomes your feedback at email@example.com.