HOUSTON -- Astros slugger Yordan Alvarez was starting to wonder if he’d ever hit another home run at Minute Maid Park, especially after rocketing a ball that had a 109.6 mph exit velocity in the eighth inning of Thursday’s win over the Royals and watching it get caught in front of the Houston bullpen in right-center field.

Alvarez stood in the dugout with his helmet on in disbelief for a few minutes, pondering what else he needs to do to homer at home. Those frustrations were erased in Sunday’s 7-2 win over the Royals when he clubbed his 29th and 30th homers of the season. The Astros swept the four-game series and have won five in a row.

Alvarez became the second Astros player in history to hit at least 30 homers in four consecutive seasons with his sixth multihomer game of the season. Hall of Famer Jeff Bagwell hit at least 30 homers in eight seasons in a row (1996-2003).

“Obviously, it’s a big goal, and every single time I go out there, I try to give it my all and give my best, and the numbers will show up,” Alvarez said.

Alvarez clubbed his first home run at home since June 22 -- a span of 105 plate appearances at home -- when he took Royals starter Alec Marsh deep to right field in the fourth, and he added a leadoff homer to center in the sixth off Sam Long. Jon Singleton hit a two-run homer in the fourth.

“When I hit the ball [in the fourth], there was a stress that just left me,” Alvarez said. “Obviously, it had been a while. I hadn’t been hitting the ball hard [enough] for homers here, so I hit that one, and then came the other one and almost a third one came. Hopefully, that bad streak is gone now.”

In the eighth inning, Alvarez fell victim to the right-center field spot once again. That fly ball had a 105.4 mph exit velocity and traveled only 366 feet, denying the slugger his second three-homer game in five days. Astros players have been wondering why balls die in right-center.

“It’s cursed,” Alvarez said. “We don’t know. Sometimes I hit a ball like that on the road and the ball gets out, and I hit it here and it doesn’t.”

Royals manager Matt Quatraro could only chuckle at Alvarez’s power prowess.

“He's one of the elite hitters in the game,” he said. “He doesn't strike out [all the time]. He covers multiple pitches. He uses the whole field. He hits for power. There's a reason he's a perennial All-Star and somebody that's the feared hitter in the league.”

The Astros (75-62) improved to a season-high 13 games over .500 and are a Major League best 68-43 since April 27. Houston also now owns the tiebreaker over the Royals by taking the season series over Kansas City, 4-3.

The Royals swept the Astros in Kansas City in April, outscoring them, 28-8, in the process, but Houston’s pitching was in tatters and Alex Bregman was off to a slow start. Things have changed in almost five months.

“That’s a pretty good Royals team,” Astros manager Joe Espada said. “They’ve been playing very well. They’re a dynamic club and they kicked our butt early in the season. We went to Kansas City and we were not playing our best, but that's why you play 162. We are getting closer to our goal, and we’re playing with a different intensity and focus and we demonstrated that this series.”

While Alvarez and Singleton did the heavy lifting at the plate, the Astros’ pitching has been stellar. Ronel Blanco (10-6) needed 101 pitches to complete five scoreless innings, walking four hitters and striking out three, to win for the first time since July 9.

In the month of August, the Astros’ 2.51 ERA was the best in the Major Leagues and their .185 team opponents’ batting average was the second lowest in any month by any team in Major League history. With All-Star slugger Kyle Tucker possibly set to return this week, the Astros look like a team poised to make another long postseason run.

“I spoke about this in the past,” Alvarez said. “I said there was going to be a moment we would all click, and that’s what’s happening right now.”