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Chris Volstad is not thinking about his winless skid. He's just trying to make better pitches.

Volstad gave up a three-run homer to Brett Wallace and remained winless in 23 starts, the Chicago Cubs' 10-1 loss to the Houston Astros on Tuesday night.

"The past is in the past, so the only thing I'm concerned with is my next game," Volstad said.

Fernando Martinez also hit a three-run homer, backing Lucas Harrell's eight strong innings for Houston.

Harrell (10-8) scattered six hits and struck out six, helping the Astros win for only the third time in their last 28 road games. Harrell has allowed two runs or fewer in all seven of his starts since the All-Star break.

"Harrell came right after us," Cubs manager Dale Sveum said. "Looked like he threw probably 90 percent fastballs. We didn't capitalize on his aggressiveness at all."

Volstad (0-9) lasted just five innings, allowing eight hits and four runs in his latest bid for his first big league win since July 10, 2011. He is approaching the major league record of 28 held by Cliff Curtis, Matt Keough and Jo-Jo Reyes.

"There was nothing real crisp going on," Sveum said. "The command, getting the ball up. The off-speed stuff, that's what was getting hit hard."

In Volstad's first two outings since being recalled from Triple-A Iowa on Aug. 1, he allowed just five runs in 13 innings. He wasn't as sharp on Tuesday, but still sees some positives.

"I had a really good changeup," Volstad said. "Sinker had some good action on that. Fastball was down for the most part. Probably one or two that were elevated a little bit. I would say as far as consistency, that's getting better."

Volstad fell to 0-14 with a 5.51 ERA during his winless skid, which has been dotted with quality outings here and there.

Scott Moore added a solo shot and double twice for a career-high three extra-base hits. Jose Altuve doubled twice and had three of Houston's 13 hits.

Darwin Barney drove in the Cub's run with a fielder's choice in the seventh.

The Cubs have lost 12 of 14 and matched their season high by falling 25 games under .500, their worst record since finishing the 2006 season 30 games below break-even.

Harrell retired the first eight Cubs before Volstad singled with two outs in the third, his first hit of the season. Harrell induced two double plays and nearly got a third when Barney just beat Tyler Greene's relay in the seventh, allowing Starlin Castro to score.

Harrell got plenty of support in Houston's biggest offensive outburst since scoring 11 runs in Chicago on June 10 against the White Sox. Houston had scored just 11 runs combined in its last six losses on the road.

"Isn't that nice?" Astros manager Brad Mills said. "Besides swinging the bat, we made some defensive plays. Lucas comes out and gives us just an absolutely quality start, and gives us that opportunity."

Wallace's homer to dead center in third gave Harrell an early cushion.

Houston's five-run sixth was aided by Castro's error on a likely double-play ball, his 18th miscue of the season. He tied Pittsburgh third baseman Pedro Alvarez for the most errors in the majors.

Moore doubled in Altuve in the first to open the scoring and kick off his best night as a big leaguer. Moore, who broke into the majors with the Cubs in 2006, doubled and scored in the sixth and hit a solo homer to right in the seventh.

Volstad will get another shot at breaking his funk in five days, when Sveum hopes he will see more of what he showed in his two previous starts.

"After a couple of good outings, even the outing in Triple-A, it was kind of based around one pitch," Sveum said. "I think he'll tell you his stuff wasn't what it was the last couple of outings."

NOTES: Mills said RHP Francisco Cordero (sprained ligament in toe) likely won't return until Sept. 1. ... The Cubs announced that Albert Almora, their top pick in June's draft, had been promoted from rookie league Mesa, Ariz., to Class-A Boise. Almora, 18, hit .347 with one homer, 13 RBIs and five steals in 18 games for Mesa. ... Sveum said RHP Matt Garza had not been ruled out for the season, but was still more than a week away from resuming throwing. Garza was placed on the disabled list on July 28 because of stress reaction in his right elbow.