CINCINNATI -- After they took the season opener from the Pirates, the Reds haven’t solved the riddle of Pittsburgh since. Monday’s 8-5 loss in Game 1 of a day-night doubleheader at Great American Ball Park was Cincinnati's sixth in a row when playing the Bucs.

“We had a chance there late,” Reds manager David Bell said. “We felt like we were going to come back there and tie it. That’s a good feeling to have when you believe in where we are offensively. Overall, we didn’t get it done.”

• Box score

Here are three takeaways from Game 1:

1) Bullpen drops the ball
The Reds’ bullpen came into Monday with the National League’s best ERA at 3.56. But the Pirates were able to score five runs against Cincinnati relievers after the departure of starter Luis Castillo.

Things went sideways in the eighth when David Hernandez allowed a double to Cole Tucker that center fielder Nick Senzel made a long run to reach, but just missed catching.

“We’re a tough play away out there in center field, with Nick coming in and trying to make a play,” Hernandez said. “That would’ve been two outs, nobody on. I think, give him a year or two, or even towards the end of the season, he makes that play easily.”

Next, Hernandez hit Adam Frazier with a full-count pitch and thought he had struck out Brian Reynolds but didn’t get the call from plate umpire Laz Diaz. On a 2-2 pitch, Reynolds ripped a two-run triple to the wall in left-center field out of Senzel’s reach.

“I haven’t looked at it, but it looked good to me,” Hernandez said of the call he didn’t get. “I still have to make pitches after that.”

Starling Marte put the game away when he slugged a 1-1 Hernandez pitch for a two-run homer to right-center field.

“That was just a flat slider, middle-away,” Hernandez said. “I feel like if I throw him a good one down and away, it’s not a home run.”

With 27 appearances each, Hernandez and Amir Garrett are tied for the second-most games pitched in the NL.

• Game 2: Iglesias' first career grand slam leads way in win

2) Defensive miscues hurt Castillo
Behind three straight two-out doubles in the bottom of the fifth, the Reds gave Castillo a 3-1 lead. Senzel drove in Jose Iglesias with his double to right-center field and scored on Joey Votto's double to right. Votto scored on Eugenio Suárez's drive off the top of the center-field wall.

But misfortune found Castillo in the top of the sixth, when defensive mistakes prolonged the inning. On Elias Diaz’s grounder to shortstop with no outs and two men on, Votto dropped the throw to first base that would’ve completed a double play. Next, Iglesias fielded a Kevin Newman grounder at shortstop and attempted a no-look glove flip to second base that sailed over Derek Dietrich’s head and allowed another run to score.

“I mean it’s so rare, you don’t even want to put any life toward that,” Bell said of the plays that went wrong. “José, I mean, I’m surprised he didn’t make that play. He makes every play. He makes them in such a free way that you just never want to think about taking that away from him. It didn’t work out there, but that’s truly what makes him a special defender. It was a factor, for sure, in today’s game.”

Garrett took over and allowed Gregory Polanco’s game-tying RBI single. Thus, Castillo received a no-decision. He was charged with three runs (two earned) and six hits over 5 1/3 innings, with four walks and four strikeouts.

“I think that's part of the game,” Castillo said of the defense via translator Julio Morillo. “It happens, but it's nothing I can control. My only job is to try to pitch [in the strike zone] and make them hit ground balls, but after that, whatever happens, happens. That I cannot control.”

3) Votto stays in a groove
On the positive side for Cincinnati, Votto had another three-hit game, with an RBI and two runs scored. He has reached safely in 16 consecutive games and has at least two hits in each of his past four games -- two of those being three-hit days.

Votto, who has raised his line to .242/.340/.366 over the four games, appears to have shortened his swing as he chokes up on the bat. After his fifth-inning double, he hit a one-out single in the seventh inning and led off the ninth with a single, after which he scored on Curt Casali’s sac fly. Both singles were hit to the opposite field.

“We know how important he is to our team,” Bell said. “With the hits, even for him, the confidence starts to roll. That’s been great.”