With Keuchel becoming the first Astros starter in three weeks to work seven innings into a game and Castro providing the big blast to spoil a solid start by the Pirates' Kevin Correia, the Astros beat fading Pittsburgh for the second game in a row to improve to 10-10 in September.
"I think today the star's got to be Keuchel," Astros interim manager Tony DeFrancesco said. "He was effective down in the zone today. He kept us in the game. He made some big pitches when he had to. I thought he was in control the whole game."
Keuchel's plan of attack was simple: mix his two-seam fastball with a backdoor slider-cutter that he's been working on, and keep the ball down in the zone.
"It was kind of pick your poison tonight whether they wanted to swing at something that looked like a ball coming in for a cutter, or the two-seam working away from them," Keuchel said. "That's the best game I've felt, and I have to give Castro all the credit in the world, because he called an excellent game."
Keuchel (3-7), who won two starts in a row, retired the last 10 batters he faced. He improved to 3-3 with a 2.95 ERA in 10 starts at Minute Maid Park this year, and each of his three career wins have come at home on a Saturday.
"That's when he's at his best, is when he's able to spot up with his cutter and with his sinker and kind of interchange those two and get guys to kind of guess," Castro said. "As long as he's keeping the ball down like that, he's going to get a lot of roll-overs and balls pounded into the ground, and that's what he did tonight. He did a tremendous job all night."
The first three batters reached in the first against Correia (11-10). Jose Altuve beat out an infield single, but was thrown out at second trying to steal. Scott Moore followed with a double, went to third on a wild pitch, and scored on a Brett Wallace single to center.
The game started ominously for Keuchel when the first two batters reached on hits. But he escaped the jam by getting Andrew McCutchen to hit into a double play and striking out Garrett Jones.
"I was able to settle down a little bit, and I think I was 2-1 on McCutchen and I was still able to get a good pitch in there, a two-seam down," said Keuchel, who gave up a solo homer to Gaby Sanchez in the second. "[McCutchen] was able to hit it right to [third baseman] Dominguez and [McCutchen] has great speed, so I didn't want him to hit it hard, but right at somebody. And that was the case."
Correia plowed through the Astros' lineup, giving up just two singles and a walk from the second through the sixth innings before Jed Lowrie led off the seventh with a bloop single. Dominguez hit a potential double play to sure-handed shortstop Clint Barmes, who booted it to allow runners at first and second with no outs. The error was costly.
That's because Castro lofted a 2-1 pitch into right field and just over the wall, to give the Astros a 4-1 lead. Castro tried to bunt earlier in the at-bat, but opted against it after the Pirates' defense crashed hard toward the plate.
"Correia did a good job tonight as far as making guys hit his pitches and he was able to hold us down for most of the game," Castro said. "We caught a big break there on Dominguez's ball and he just left up a changeup enough for me to get enough of the bat on it. I was looking to advance the runners the best I could and it ended up working out."
Barmes, who played with the Astros last year, lamented the gaffe.
"If I had it to do over, I'd do it different. Catch it and flip it to [Neil] Walker," he said. "However you look at it, those are plays we have to make in close games. You pretty much have to do all the little things. One time we make a mistake and the other team capitalizes and hurt us."
Castro's home run barely cleared the fence in right field, where Jones leaped at the fence and lost both the ball and his glove.
"He made a lot better play than I anticipated him making," Castro said. "As soon as I saw him go up, I kind of saw the ball bounce up. I didn't know he lost his glove until the replay. He made a great effort for it and luckily he just missed it."