Seattle, WA (My Sportsbook) - Kory Casto picked the perfect time for his first major league home run, as his pinch-hit three-run shot in the eighth inning led the Nationals to their first three-game sweep of the season with a 6-2 win over the Nationals.

Casto, who played college baseball at the University of Washington, hit the home run in front of some of his friends and family.

"I got a fastball elevated over the plate and I put a good swing on it and it barely hung on, but it hung on enough," Casto said. "That's a pretty awesome thing, first one of my career on Father's Day, and it's a go-ahead-for-the- sweep home run, so that's a big deal."

After Aaron Boone doubled off Mark Lowe to lead off the eighth, Lowe attempted to throw out Boone at third on Felipe Lopez's bunt, but was unsuccessful. With runners on first and third and nobody out, Casto, a 27-year-old outfielder called up to replace the injured Ryan Zimmerman, hit a drive deep down the right field line, bouncing off the pole for the deciding blast.

Elijah Dukes added a sacrifice fly later in the inning for the Nationals' sixth run of the game.

Jesus Colome (2-1) got the win after working two innings of shutout relief to give the Nationals their fourth win in the last six games. Starter Tim Redding pitched six solid innings, giving up two runs -- one earned -- on five hits, earning his fifth straight no-decision.

"I think (Redding) did a very good job for us," Acta said. "We played shaky defense in one inning. He really battled in that inning and pretty much got himself out of it. Colome came in and was lights out."

In their 12-hit attack, five Nationals had multi-hit games. Lastings Milledge led the way with three hits and a sacrifice fly. Boone added two doubles and a run scored.

Mark Lowe (1-3) allowed an inherited runner to score in the seventh and gave up four more runs in the eighth for the loss. Jarrod Washburn pitched six innings, giving up two runs for his second consecutive quality start.

The Mariners have now dropped four of six and are a league-worst 24-45. Ichiro Suzuki was the lone Mariner to post more than one hit, going two for five with one RBI.

"It's been terrible. We find a different way to lose every night," Washburn said. "We're just not good. We're not playing good baseball and we haven't shown any signs of turning it around. It's frustrating, it's embarrassing."

The Nationals got on the board early with an RBI groundout from Jesus Flores after Washington loaded the bases with one out in the first.

Seattle tried to answer in the first after hitting back-to-back singles with two outs, but Redding got Jose Vidro to ground out to end the threat.

Felipe Lopez committed two errors on one play to start the third, bobbling the ball and then making a bad throw, allowing Jose Lopez to get to second base. After an Raul Ibanez fly out and a Adrian Beltre groundout got Lopez to third, Redding induced Vidro into a fly ball to right field, but Dukes dropped the ball - the Nationals' third error of the inning - tying the score at one run apiece.

Washburn ran into trouble again in the fourth after allowing a double and a walk with one out, but got Wily Mo Pena to ground out into a double play to end the inning.

In the bottom of the fourth, after Willie Bloomquist singled and stole second with two outs, Suzuki hit an RBI single to give the Mariners a 2-1 lead.

After Washburn started the seventh by giving up a double and a walk, he was lifted for Lowe. Following an infield single and a fly out, Flores added another RBI groundout to tie the score at two. Lowe then struck out Ronnie Belliard looking to end the threat.

Game Notes

Suzuki extended his interleague game hitting streak to 26 games, dating back to July 2006...Since moving to Washington, the Nationals have never lost to the Mariners (6-0)......The previous Nationals three-game series sweep was September 24-26 against the Mets..The Mariners have lost seven consecutive home games, the longest franchise streak since losing eight in a row in 1996.