PITTSBURGH -- Kyle Freeland would have only taken one pitch back on Monday night if he had the chance. That’s pretty good considering the veteran left-hander threw 100 of them.

However, that one pitch made the difference as the Rockies lost, 2-0, to the Pittsburgh Pirates at PNC Park in the opener of a three-game series.

Rodolfo Castro hit a two-run home run off Freeland in the seventh inning to snap a scoreless tie. That was all the Pirates needed, as Mitch Keller threw a four-hit shutout for his first career complete game.

Castro hit a four-seam fastball into the bullpen in center field after former Rockies outfielder Connor Joe led off the seventh with a single.

“The first pitch [to Castro] was a pitch up and away, and he fouled it off,” Rockies manager Bud Black said. “Kyle was trying to throw the fastball in, which was really effective for Kyle tonight, and that fastball sort of leaked out over the middle part of the plate and [Castro] has some power. It happens. What a great, great pitchers’ duel, though.”

Freeland did not second-guess the pitch selection. He just wished he had executed the fastball better in that spot.

“We were trying to jam him up and in there and get a double play,” Freeland said. “I was definitely trying to pitch to contact to get a two-for-one special there. I’m one of the guys who has been leading the league in double plays since I came into the league, so I’m always looking for a double-play ball.”

Instead, Castro hit the ball out of the park. Freeland, though, was philosophical about being on the losing end of the pitchers' duel.

“That’s baseball,” he said. “Keller has been on a heater all year, and he was on a heater tonight. All you can do is give him credit. He dominated our lineup tonight, which is hard to do.”

Freeland scattered seven hits over seven innings while allowing two runs. He struck out four and walked three, showing no signs of the neck strain that forced him from his previous start after pitching five scoreless innings against the Milwaukee Brewers.

Catcher Elias Díaz gave Freeland some defensive help. Díaz completed two inning-ending double plays by throwing out runners attempting to steal.

The last time a Rockies catcher completed two double plays with caught stealings in the same game was Yorvit Torrealba in 2006 against the Los Angeles Dodgers.

“I can’t thank him enough,” Freeland said of Díaz. “That’s top-tier defense right there. He’s always working his butt off behind the plate for me.”

On April 17, Freeland was tagged for nine runs (seven earned) over 2 2/3 innings in a loss to the Pirates at Coors Field. Pittsburgh swept that three-game series, outscoring the Rockies by 24 runs (33-9).

“I’ve got to give the Pirates a lot of credit, because in that game, they really laid off the low curveball, which is one of my best pitches that I usually get swings and misses or weak contact on,” Freeland said. “We had to change things up this time.”

The different game plan worked, except for the fateful pitch to Castro in a game that lasted just one hour and 55 minutes.

“That was a well-pitched game on both sides,” Pirates manager Derek Shelton said. “You don’t play a game under two hours if both guys aren’t really good.”