Lefthander Hector Santiago is expected to be an upgrade over his predecessor, Ricky Nolasco. But in his Target Field debut for the Twins on Tuesday night, Santiago encountered some of the same problems as the man he was traded for on Aug. 1.

Santiago fumbled away a two-run lead in the sixth inning and Houston beat the Twins 7-5, only the Astros' third victory of the month.

The Twins did score a run in the ninth, and Joe Mauer drew a two-out walk to bring the tying run to the plate. But new Houston closer Ken Giles struck out Max Kepler to end the game.

Santiago fell to 10-6 and is 0-2 in his two starts with the Twins after winning all six of his July starts while with the Angels. Plenty of pitchers would take 10 victories at this point. Santiago's résumé includes problems with walking batters, high pitch counts early in games and lots of long balls — batters have hit 23 homers off him.

And Twins fans definitely saw all sides of Santiago. He gave up four earned runs over 5⅓ innings on five hits and two walks with five strikeouts, throwing 83 pitches. Santiago threw 99 pitches in five innings Thursday at Cleveland in his first start for the Twins, and he worked between starts to clean some things up.

"The [previous] four days we have been trying something a little different, just trying to be in the zone a little bit more," he said. "The end result wasn't what we wanted, but you could see the difference in pitch counts."

Houston took a 2-0 lead in the first inning, and it could have been worse. Alex Bregman hit a one-out double but was thrown out at home by center fielder Eddie Rosario trying to score on Jose Altuve's single. But Carlos Correa followed with a home run to left.

Santiago went to 3-2 counts five times over the next four innings but reached the sixth without any more damage, and he was rewarded with a lead.

Miguel Sano smashed Mike Fiers' first pitch of the second for a home run to make it 2-1. Three innings later, Robbie Grossman, who broke in with the Astros in 2013 and played 190 games with them over three seasons, hit a two-run homer, and that was promptly followed by Brian Dozier's solo shot for a 4-2 Twins lead. It was the 10th time the Twins have hit back-to-back home runs this season.

Santiago had a two-run lead heading into the sixth and proceeded to do what Nolasco frequently did — hand it back.

The first three batters of the sixth reached base, with two scoring on Correa's single off the wall in right. The second run was unearned, as Kepler dropped the ball while trying to get a throw off. A third run scored on a groundout, and Houston led 5-4. That was all for Santiago, who threw 83 pitches over 5⅓ innings.

"They just kept coming," Twins manager Paul Molitor said, "and put together a rally with a leadoff hit in the sixth."

In two starts with the Twins, Santiago has given up eight earned runs over 10⅓ innings.

The Twins had chances to get back in the game but were 1-for-11 with runners in scoring position. The lone hit came when Jorge Polanco singled in the sixth inning with Trevor Plouffe on second. But Plouffe was thrown out at home by a spot-on throw from Jake Marisnick in center.

"Those are tough to take," Molitor said, "when you take a lead and can't finish."