SEATTLE -- Welington Castillo was ready to speak about his big day for Arizona only to pause when something on the television caught his attention.

"Wait, that's me," he said.

Tough to fault Castillo for wanting to stop watch highlights of his two home runs, especially when they came against Seattle ace Felix Hernandez.

"He's a really good pitcher. He's one of the best," Castillo said. "I think I was guessing right."

Castillo hit a pair of home runs off Hernandez, including a two-run shot in the first inning sending Arizona to an 8-2 win over the Mariners on Wednesday a fifth straight win for the Diamondbacks.

Arizona completed its first sweep of Seattle and fifth this season thanks Castillo's two long balls. Castillo hit a two-run homer off Hernandez (12-6) as part of Arizona's four-run first inning, then added a solo shot leading off the fourth inning. He became just the sixth player to homer twice in the same game off Hernandez.

Castillo, who was on Seattle's roster briefly earlier in the season before being traded to Arizona, homered three times in the series.

"Just giving him at bats. He's a good hitter," Arizona manager Chip Hale said. "We saw him in spring training with Chicago and knew he was a good hitter. Couldn't figure out why he wasn't getting much playing time. ... Just giving him the opportunity has been great. I think he's been a good leader for our staff (and) he's been swinging the bat really well."

Patrick Corbin (2-3) allowed just one run and three hits in six innings, winning for the first time since his season debut on July 4 as he continues to come back from Tommy John surgery. Corbin struck out six and rolled through Seattle's lineup. Brad Miller's two-out RBI single in the fourth was the only damage against the left-hander, who needed just 80 pitches to get through six innings.

"It's all about pitching for us and if we continue to do that we should be making a run here," Corbin said.

Paul Goldschmidt added a two-run single and David Peralta added a two-run triple as the Diamondbacks won for the seventh time in 10 games.

Arizona was aggressive against Hernandez early in the count and it paid off in the first inning with Goldschmidt's two-run single before the first of Castillo's home runs. It was just the sixth time in 324 career starts Hernandez allowed four or more runs in the first inning, including giving up eight runs in the first to Houston earlier this season.

Arizona finished with 12 hits off Hernandez, a season-high allowed and most since 2013 against the Angels. Peralta capped the Diamondbacks big day with a two-run triple in the seventh on a deep fly ball to right-center field that likely should have been caught.

"You have to capitalize on any mistake he's going to make," Hale said. "Our guys were ready. They really put good swings on pitches because they had to."

CROOKED CROWN

The seven earned runs were the most allowed by Hernandez since giving up eight runs and failing to make it out of the first inning against Houston on June 12. In the seven starts since that game in Houston, Hernandez had allowed eight earned runs total.

"His command was off. He left a lot of pitches in the middle of the plate," Seattle manager Lloyd McClendon said.

TRAINER'S ROOM:

Diamondbacks: Right-handed reliever Randall Delgado was placed on the 15-day disabled list with a sprained right ankle. Delgado was hurt working out before Tuesday's game. Addison reed was recalled from Triple-A Reno.

Mariners: Robinson Cano was out with an abdominal strain. An MRI revealed a Grade 1 strain, but Cano was traveling with the team on its road trip. McClendon said they hope Cano can step in at designated hitter in a few days. Cano was injured making a play in the field in Monday's game against Arizona and played through the discomfort on Tuesday.

UP NEXT

Diamondbacks: Arizona continues interleague play with three games at Houston. Rubby De La Rosa (8-5) gets the start in the opener. He's given up just one earned run in his last 15 innings.

Mariners: Seattle opens a key four-game series with Minnesota on Thursday. J.A. Happ (4-5), who lasted just 1 2/3 innings in his last start, takes the mound for the Mariners.