Double-A Tulsa pitching coach Bill Simas knows how impressive Yadier Álvarez can be when he controls his fastball. So when he Alvarez issued six walks in his last start, the two went back to the drawing board.

One week later, against the same opponent, the Dodgers' third-ranked prospect produced much better results.

Alvarez allowed three hits and two walks while striking out five over a career-high six scoreless innings Saturday as the Drillers defeated San Antonio, 3-2, at ONEOK Field. The right-hander, who had not won since June 26, picked up his first victory in the Texas League.

"I saw good preparation throughout the week," Simas said. "And he was out there and had good energy, focus and tempo. He managed counts with his two-seam fastballs and minimized solid contact. It was a good outing for him."

In five starts since a promotion from Class A Advanced Rancho Cucamonga, Alvarez (1-1) owns a 2.66 ERA and 1.65 WHIP with 26 strikeouts over 23 2/3 innings. He pitched five innings -- which matched his previous high -- against the Missions a week ago but allowed two runs on three hits with those six walks. Simas saw a much better version of Alvarez this time around.

"He's really worked on the side on fastball command and release point and figuring out how his body works," Simas said. "But the biggest thing tonight was the two-seam fastball that he controlled in the zone. His slider was good all night, it played well off of the fastball. And he also mixed in some changeups. But the big difference was the fastball command."

MLB.com's No. 51 overall prospect set down the first four hitters on 12 pitches before Ty France beat out an infield hit and Webster Rivas walked with one out in the second. Undeterred, Alvarez fanned Nick Schulz , then induced a groundout from Auston Bousfield .

Gameday box score

"I think it was in the second, but also kind of in the first that you could tell he was in control of the strike zone and it could be a good night," Simas said. "Then you could see the confidence on his face and you felt comfortable about it from there."

The 21-year-old threw a perfect third before issuing a leadoff walk to Padres No. 10 prospect Josh Naylor in the fourth. Franmil Reyes bounced into a double play, but France singled again. Alvarez again worked out of trouble by punching out Rivas.

Having a feel for his entire repertoire, the Cuba native set down six of the last seven hitters he faced to finish off the longest outing of his two-year professional career. In all, he threw 51 of 83 pitches for strikes and recorded nine ground-ball outs. Alvarez, who stands 6-foot-3 and weighs 175 pounds, used his size to his advantage.

"He has some length and the batters don't pick up the ball off of him," Simas said. "He's blessed with an arm with velo, and you put velo with movement in the zone. His breaking ball is good enough to keep them off the heater. It's just angle -- he has long limbs. It might be tough to pick up a little bit. When he's in the zone, they don't make solid contact.

"Tonight, he put a full game together. In the past, he'll walk six but punch out eight. He's shown flashes of it, but tonight he minimized his pitch count and he used his two-seam fastball in the zone, which was the biggest difference. From start to finish, he was good."

In 19 outings, including 16 starts, across two levels this season, Alvarez has a 4.55 ERA and 1.51 WHIP with 87 strikeouts over 83 innings. Simas said he's been impressed with the way the youngster continues to fine-tune his approach.

"I just see him putting more time in between sides, really trying to figure things out," Simas said. "He's really trying to feel for the process of command. He has a smile on his face and he's happy. He's in a good place right now."

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On the offensive side, Garrett Kennedy delivered a solo homer and Matt Beaty collected three hits, including a double, for the Drillers. Fifth-ranked Dodgers prospect Yusniel Díaz went 2-for-4 with a walk and a run scored.

Padres No. 13 prospect Enyel De Los Santos (9-5) started for the Missions and gave up three runs -- two earned -- on six hits and three walks with six strikeouts in six innings.

Andrew Battifarano is a contributor to MiLB.com. Follow him on Twitter, @AndrewAtBatt.