SAN FRANCISCO -- Logan Webb got the best of Framber Valdez in a clash between two of the premier sinkerballers in the game, tossing six solid innings to lead the Giants to a 5-3 win over the Astros in Wednesday afternoon’s series finale at Oracle Park.

Webb allowed three runs on seven hits while walking none and striking out five, marking the seventh straight outing in which he’s completed at least six frames.

Austin Slater went 3-for-5 with two RBIs, and Heliot Ramos, Wilmer Flores and Matt Chapman drove in one run apiece to help back Webb, who improved to 6-5 with a 3.02 ERA over a Major League-high 92 1/3 innings this year.

“He’s one of the best pitchers in the league,” former Giants teammate and current Astros utility man Mauricio Dubón said. “He’s an ace. He showed it today. He stopped one of the best lineups in baseball.”

After back-to-back series wins against the Rangers and Astros, the Giants (34-35) will have a chance to climb back to .500 when they continue their run against American League West competition and take on the Angels in a three-game set beginning on Friday night at Oracle Park.

Webb’s line would have been even more impressive had he not committed a mental mistake that allowed the Astros to get on the board in the fourth inning. After Yordan Alvarez doubled and advanced to third on a groundout, Webb coaxed a potential inning-ending grounder from Jeremy Peña, but he was too slow to cover first base on the play, allowing Peña to reach safely and bring home Alvarez.

“Off the bat, I just thought it was going right to the second baseman, so I didn’t think twice about it,” Webb said. “And then I saw [the first baseman Flores] go for it. Any time the ball goes to the right side, you’ve got to get over, so that’s on me.”

Alvarez came back to do more damage against Webb in the sixth, hammering a below-the-zone changeup out to left-center-field for a two-run shot that cut the Giants’ lead to 5-3. It was only the fourth homer Webb has permitted in 15 starts this year.

“The two pitches -- the double and the home run -- I threw both of those pitches exactly where I wanted to throw them,” Webb said. “I feel like the type of hitter that he is, you’ve just got to tip your cap. That’s the first time I’ve seen a changeup underneath go out the other way. You’re kind of in awe as it happens. When he first hit it, I was like, ‘There’s no way,’ and then it just kept kind of going. But I guess you tip your cap. He’s one of the best pure hitters in baseball.”

Webb needed only 83 pitches (57 strikes) to get through six innings and would have liked to pitch deeper into the game, but he felt a zinger in his right shoulder after throwing out Ezequiel Duran at first base for the final out of his last start against the Rangers on Friday. Webb doesn’t believe the issue is serious, but the Giants decided to cap him at 90 pitches on Wednesday as a precautionary measure.

“I trust [manager] Bob [Melvin] with every decision,” Webb said. “And I agreed with him, to be honest. I feel great, but I think it’s a long season, and we’ve got a long way to go. I get why we were a little cautious with that.”

Since the start of the 2021 campaign, Valdez (63.7 percent) and Webb (60.3 percent) rank 1-2 in groundball percentage among 158 pitchers with at least 750 batted ball events in that span. The two aces previously matched up at Minute Maid Park on May 23, 2023, when Webb also outdueled Valdez by firing 7 2/3 innings of two-run ball to earn the win.

The Giants got Webb some early run support Wednesday, nicking Valdez for two runs in the third behind Flores’ sacrifice fly and Chapman’s two-out RBI double to center field. They maintained their aggressive approach against the left-hander in the fourth, loading the bases with one out to set the table for Slater’s two-run single. Ramos plated another run with a sacrifice fly, extending San Francisco’s lead to 5-1 and knocking Valdez out of the game after a season-low four innings.

“You try to keep the ball off the ground,” Melvin said. “Slater’s approach -- up the middle the other way -- that’s why you keep [Valdez] in the air. It kind of keeps you on time for a breaking ball if you’re ever going to try to pull him, which you shouldn’t. We got some good at-bats and made him throw some pitches.”