SEATTLE -- That was vintage Felix Hernandez.

The longtime Seattle ace, who was sidelined for nearly two months this season with shoulder problems, pitched six scoreless innings and Nelson Cruz hit a home run as the Mariners defeated the Oakland Athletics 4-0 on Sunday afternoon at Safeco Field.

"He had a different look about him today," Mariners manager Scott Servais said of Hernandez. "Hands down, his best stuff (of the season)."

Hernandez (4-3) allowed two hits, walked three and struck out a season-high eight. The right-hander, who was making his fourth start since coming off the disabled list -- he was out from April 26 to June 22 with inflammation in his right shoulder -- lowered his ERA from 5.04 to 4.44.

The only hits Hernandez allowed were a one-out double to Matt Joyce in the third inning and a two-out single to Jaycob Brugman in the fifth.

"From fastball to changeup, all the pitches were working," Hernandez said. "I'm healthy and feeling good."

As for the season high in strikeouts?

"When you have good stuff ..." Hernandez said.

Hernandez now has 2,310 career strikeouts, passing Juan Marichal for 49th on the all-time list.

"It's an honor," Hernandez said.

Hernandez got his first strikeout when he fanned Matt Chapman with two on to end the second inning. Hernandez struck out two batters in each of the next three innings, and capped his day by getting Jed Lowrie to swing at a third strike to end the sixth.

"He stepped it up. You could see that from the beginning," Servais said. "He needed to get deep and give us a chance to win.

"He doesn't have to throw nine shutout innings. He got a lot of ground-ball outs early and then put up strikeouts. He still has effective stuff."

It was Hernandez's 24th career victory against the A's, breaking a tie with Frank Tanana for the most by an opposing pitcher since the team moved to Oakland in 1968.

"We've seen him good plenty of times. It didn't look a whole lot different," A's manager Bob Melvin said of Hernandez. "Looked like his velocity might have been a little bit better than we were seeing in video recently, think he hit 92, maybe 93. But, as he does, he mixed it up, pitched backwards and throw more curveballs than we're used to seeing. He was really good."

Seattle's Tony Zych, Marc Rzepczynski, Nick Vincent and Edwin Diaz combined for three hitless innings of relief to cap the victory.

Cruz's two-run homer to right-center field in the fourth inning gave the Mariners a 3-0 lead against A's right-hander Daniel Gossett (1-4). It came after fellow All-Star Robinson Cano led off with a double.

Cruz, who will be the designated hitter for the American League in the All-Star Game, has been battling nagging hamstring and knee injuries for weeks.

"He's unbelievable," Hernandez said. "He just wants to be in the lineup every day."

The Mariners opened the scoring in the third, as Jarrod Dyson led off with a walk, moved to third on a single to shallow left field by Carlos Ruiz and scored when Jean Segura grounded into a double play.

After Cruz's homer, the Mariners tacked on a run in the seventh. Danny Valencia walked, went to second on a single by Dyson and scored on Ruiz's single to left.

Gossett, a rookie, allowed three runs on five hits in 4 1/3 innings. He walked two -- the first time he has walked more than one in six career starts -- and struck out four.

"I thought he threw the ball pretty well," Melvin said. "At that point (in the fifth inning), with four days off and a loaded bullpen, I just couldn't give up another run. ... Third time through the middle of the order, I just felt like it was time for him to come out."

The Mariners (43-47) won for just the second time in their past 11 home games to split the four-game series with Oakland (39-50).

NOTES: Seattle DH Nelson Cruz heads into the All-Star break with 70 RBIs, the franchise's first player to reach that mark at the break since Raul Ibanez in 2006. ... Mariners C Carlos Ruiz, who entered the game with a .194 average, went 3-for-3 to improve his average to .227. ... Oakland LF Khris Davis struck out once and has fanned 117 times this season, a franchise record for most before the All-Star break. ... The Mariners are 40-15 when scoring four or more runs this season. ... Mariners RHP Nick Vincent pitched a scoreless inning of relief. Vincent hasn't allowed a run in 21 appearances at home this season, spanning 20 innings. ... The A's will play host to the Cleveland Indians when play resumes Friday after the All-Star break. The Mariners open in Chicago against the White Sox, before completing a six-game trip in Houston.