PITTSBURGH -- Off a big series win against the Braves, the D-backs came into Pittsburgh and got off on the right foot with a powerful opening win Friday.

But they sputtered the next two games and dropped a series to the Pirates, who are riding high following a sweep of the Dodgers. Sunday’s 3-0 loss at PNC Park raised some questions for the D-backs, though there was a silver lining or two in the process.

Here are three takeaways from Sunday and the weekend’s series loss as a whole.

A case for ace
When Brent Strom joined the D-backs as pitching coach in the offseason, some of the Astros analysts he worked with in recent years said that if he didn’t turn Zac Gallen into a Cy Young Award contender, something had gone wrong.

“They loved him, and I could see why,” Strom said. “If you look at the computer, you look at the charts, you see stuff that looks really spectacular.”

But despite Gallen’s incredible numbers -- including a 2.40 ERA this season after his six-inning, two-run start Sunday -- there is still work to be done. Right now, the emphasis is on command, especially of Gallen’s fastball.

“It’s a work in progress,” Gallen said of the pitch Sunday. “I feel like it was more hit or miss. There would be some times where I was really on the edges, and it worked out, but I think it was really kind of ‘flip a coin’ for the most part out there.”

Gallen was able to use the high-spin four-seamer to get out of some jams, though, including a huge strikeout from a full count to Bryan Reynolds in a third-inning, bases-loaded jam that produced no runs.

That gritty mentality has allowed Gallen to be an escape artist in the few pickles he found himself in. He’s making some fixes to get in those situations fewer times, but the D-backs have all the confidence in him to clean up his mechanics and get into a better spot.

“As usual, pitchers go in waves, and he’ll go on the upswing,” Strom said. “He’ll be fine.”

All or nothing
Everything was going for the D-backs in the series opener against the Pirates. They launched five homers between four players and had another three doubles en route to scoring eight runs for the second time in a three-game span.

Whatever wave they were riding, the waters stilled Saturday and Sunday. Over those two games, the D-backs’ offense went 9-for-64. All five of their hits on Sunday were singles.

But don’t let the weak contact fool you. One of the products of that inconsistency, from D-backs manager Torey Lovullo’s perspective, was trying to do too much with one swing after making homers look easy Friday.

“We’ve got to be better,” Lovullo said. “We’re a very capable offensive team, and we have a good approach and we don’t try to do too much and have big thoughts. It looked like we were having some big thoughts based on the types I was watching us take.”

A streak comes to an end
On Saturday, Ketel Marte was about the only offense the D-backs had going, as he hit two doubles and scored the team’s lone run of the game on a wild pitch. But Sunday, his long stretch of hits came to a close.

Marte’s 16-game hitting streak, which was the longest active streak in MLB entering Sunday, was foiled after he struck out and grounded out three times.

Over those 16 games, the D-backs’ second baseman hit .390 with seven doubles and a homer.

The streak coincides with a big turnaround at the plate for Marte, who signed a five-year extension with the D-backs in Spring Training. Through his first month of the season, Marte went 12-for-82 (.146) with a .467 OPS, but he’s on the rise now -- which is no surprise to his teammates.

“He’s capable of a lot offensively,” Lovullo said, “and once he gets to that point where the swing is locked in and he gets the right sightlines and he’s driving the baseball, he’s a very dangerous hitter. But he needs to continue to work, as we all do, and we will.

“It was a great run for Ketel, and I know he’s eager to start another streak tomorrow.”