CINCINNATI -- Was Reds starting pitcher Luis Castillo sharp? No. Did Castillo have his best stuff? No. Yet, Cincinnati and Castillo still could have won Sunday's game vs. the Nationals.

Instead, an array of fourth-inning defensive mistakes and one big baserunning gaffe in the ninth meant a 5-4 loss for the Reds, as they dropped the final three games of the four-game series. 

"There's no question they win and lose as a team, which is all you can ask for," manager David Bell said. "There's a lot of things that went into the way this series went today. It didn't come down to one play."

Over 6 1/3 innings and 111 pitches, Castillo gave up five runs -- three earned -- and six hits with four walks and six strikeouts. Through six starts since his season debut on May 9, he is 2-3 with a 3.55 ERA. Over his most recent four starts, he has a 2.70 ERA.

"The changeup wasn’t working as well as we wanted it to go," Castillo said through translator Jorge Merlos. "But we kept battling throughout the game as much as possible to try to get a better outing as much as we could.”

Castillo opened a 29-pitch first inning with a walk and a double but seemed poised to escape. A two-out, two-run double by Josh Bell put Cincinnati down, 2-0. Three straight RBI hits in the bottom of the first -- by Tommy Pham, Joey Votto and Tyler Stephenson -- gave Castillo a chance to reboot his outing.

The top of the fourth inning featured multiple defensive lapses that cost the Reds their 3-2 lead.

• On Yadiel Hernandez's grounder to the shortstop, Kyle Farmer's high throw pulled Votto off first base. It was originally ruled a hit, but the official scorer later charged Farmer with an error.
• With a runner on first base, Maikel Franco hit a hard grounder to third base. Brandon Drury fielded the ball and threw to second baseman Matt Reynolds for the force. Reynolds dropped the ball during the transfer from his glove and couldn't complete a double play.

“I just couldn’t get a clean grip out of my glove," Reynolds said. "It’s a play I should make 100 percent of the time. That cost us runs. You can’t do that in the big leagues.”

• Luis García followed with a single to right field. Aristides Aquino bobbled the ball as he fielded it, which allowed Franco -- who paused at second base -- to advance to third base.
• César Hernández followed with a sharp grounder to first base. Votto fired to second base for the out but Farmer’s throw back over to first base was not in time, as Franco scored the go-ahead run. Both runs in the inning were unearned.

According to Statcast, the Reds' defense entered the day ranked tied for 22nd in the Major Leagues in outs above average (-9), and third-worst in the league at turning ground balls into outs (71.7 percent).

"I was really focused on getting ground balls in that inning, but whatever happened with the results right there, I was just battling as hard as I could and kept battling throughout the game to get a positive result," Castillo said.

Farmer, Reynolds and Aquino have been three of the Reds' top defensive players.

"Several guys came in and patted [Castillo] on the back because we knew he kept pitching and kept pitching no matter what," Bell said. "Guys take a lot of pride in making every single play. It's not going to happen, though. It's the game sometimes, certainly not lack of effort, and Luis knows that. He came back and pitched great the next couple of innings."

After Hernández’s RBI groundout in the 4th, Castillo retired six in a row with three strikeouts before Franco clubbed a first-pitch sinker for a no-doubt solo homer to left-center field in the 6th inning.

The Reds added a run in the eighth to make it a one-run game and threatened in the ninth, when disaster struck. Against Steve Cishek, Nick Senzel hustled for a two-out single to shortstop by beating the throw, putting the tying run on second base and winning run at first. On a Cishek pitch to Brandon Drury, Senzel drifted too far from the bag and was picked off by catcher Keibert Ruiz. The play was challenged by Cincinnati but the call stood and the game ended.

“He didn’t tag me. I was safe," Senzel maintained. “They made a good play but it should never have happened on my part. My fault.”