HOUSTON -- After the Astros crushed the Padres on Sunday for their fifth win in six games, manager Dusty Baker sounded a warning about a stretch of upcoming games against the A’s and Royals -- the two worst teams in the league. Baker said teams without much on the line often play like they have nothing to lose.

Baker, with roughly 50 years of experience as a player, coach and manager, proved to be prophetic. The 99-loss A’s rolled into Minute Maid Park and handed the defending World Series champions back-to-back losses against their two best starting pitchers -- Framber Valdez and Justin Verlander -- to shrink Houston’s American League West lead over Texas to one game.

The A’s came out swinging aggressively Tuesday night against Verlander and wound up tagging him for five runs over seven innings to claim a 6-2 victory at Minute Maid Park, securing a series win. The loss dropped the Astros to 37-37 at home this year.

• Games remaining: vs. OAK (1), at KC (3), vs. BAL (3), vs. KC (3), at SEA (3), at AZ (3)
• Standings update: The Astros (82-64) lead the American League West by one game over the Rangers, who have won four in a row. The Astros hold the season tiebreaker against the Rangers.

“Tough to lose these two first games, but they’re playing good baseball,” Astros outfielder Chas McCormick said. “We have to come out and be ready to play better. We had Valdez and Verlander and lost both games. They did their job.

“We’re not hitting as good as we want to, obviously, but you’ve got to give credit to Oakland. They’re playing well right now, and we need to get back on track and find a way to win tomorrow.”

Verlander gave up three runs in the first inning, capped by a two-run homer from Shea Langeliers onto the railroad tracks in left field. Former Astros outfielder Tony Kemp added a solo homer in the fifth for a 5-1 lead. Verlander struck out seven and didn’t walk any batters.

“Tough one,” the veteran right-hander said. “I felt like I had some decent stuff and they were able to capitalize, especially early on. A couple of one-run innings, those happen, but the damage was kind of already done in the first. I went and looked back and saw some decent pitches. Sometimes you’ve got to tip your cap.”

Oakland, which has the highest ERA in the AL, has held the Astros to two runs and nine hits -- one extra-base hit --  in two games. The Astros were averaging 7.4 runs and 11.8 hits per game in the 20 games prior to the A’s coming to town.

“They’re keeping our big boys off the bases -- [Jose] Altuve, Breggy [Alex Bregman], [Kyle] Tucker and Yordan [Alvarez],” catcher Martín Maldonado said. “Those big guys carry us, and they've done a pretty good job of pitching against them.”

McCormick said Verlander addressed the team in the clubhouse after the game in an effort to get them going. That’s at least the third time in the last month the Astros have had such a postgame meeting. Maldonado was one of the veterans players to address the club after Seattle swept the Astros last month in Houston, and rookie catcher Yainer Diaz said some veterans spoke up following the Yankees’ sweep at Minute Maid Park to start September.

“We can’t just come out to these games and think it’s going to be a cakewalk because it’s not,” McCormick said. “We’re getting our butts whipped. You got to give credit to them; they’re playing really well. Every team is good in this league, especially this time of year. We have to show up every single night.”

The Astros still have one final shot at the A’s before traveling to Kansas City to face the 101-loss Royals, who will also be in Houston next week and also have nothing to lose. Those games look like wins on paper, but Monday and Tuesday served as a gut-punch reminder to the Astros about the unpredictability of baseball.

“I’ve seen that many, many times, especially this time of the year,” Baker said. “They're swinging the bats. They were all over J.V. today. Even some of the outs were hard. They jumped us, really, in the first inning. …

“We’re not getting a bunch of hits. It was tough to take, but it is what it is at this point. We’ve just got to come back tomorrow and salvage this game here before we go on the road.”