Cincinnati’s Reds' Joey Votto, right, homered in the 14th inning to lift the Reds past the Nationals. (DAVID KOHL/AP)

Jordan Zimmermann’s season, one of the best by a pitcher in the Washington Nationals’ brief history, deserved a better end than the one that unfolded Sunday afternoon at Great American Ball Park. He finished his shortest start this year by walking in the go-ahead run. He skulked off the mound shaking his head with a mess behind him, a Cincinnati Red occupying each base.

The end became more painful hours later, as Zimmermann watched a loopy finish devolve into a 5-4 walk-off loss. After the Nationals rallied to take the lead in the ninth inning, Drew Storen blew a save and Collin Balester lost it in the 14th, when Joey Votto lined an opposite-field home run into the first row in left field.

The blast landed 5 hours 15 minutes after the first pitch, the longest game in Nationals history. It also rendered moot the Nationals’ myriad clutch performances — Ryan Zimmerman’s tying pinch-hit, Jayson Werth’s go-ahead single, Rick Ankiel’s miraculous throw in the ninth inning, the bullpen’s 81 / 3 patchwork innings.

“That was quite a day,” Manager Davey Johnson said. “I’ve been a part of some crazy ones. That’s right up there with them.”

The Nationals’ sixth consecutive loss momentarily obscured the importance of Zimmermann’s 2011. He surpassed the 160 innings the team allotted him in his first full year after Tommy John surgery. His success — a 3.18 ERA and 124 strikeouts compared to 31 walks in 1611 / 3 innings — may be the brightest development of this Nationals season.

They have, for years to come, a legitimate No. 2 starter. And his triumph over elbow reconstruction can provide an example to the legitimate No. 1 starter who will soon return.

“He’s going to be a staple in that rotation,” Storen said. “The way he came back, he’s going to be a good guy for [Stephen] Strasburg to learn from coming off Tommy John — being consistent every day, being healthy from beginning to the end.”

Zimmermann allowed three runs in 41 / 3 innings Sunday, striking out six while attacking with his come-and-get-it, four-seam fastball. But Votto and Jay Bruce each drilled a solo home run off him, and he came apart in the fifth.

With the scored tied at 2, the Reds loaded the bases with one out after Zimmermann yielded two singles and then hit Brandon Phillips with an 0-1 fastball. Zimmermann began Fred Lewis with a first-strike fastball, but he followed with four consecutive balls, and the go-ahead run sauntered home. Johnson emerged from the dugout and ended Zimmermann’s season.

“This start right here makes a guy want to get back on that mound,” Zimmermann said. “I got to deal with it for a whole offseason. It’s going to make me work even harder and be ready come spring training.”

He finished the year two outs shy of qualifying, at season’s end, for major league statistical leader boards. At the moment, he ranks in the top 15 among National League starters in ERA. He pitched at least five innings all 26 starts he made except Sunday and threw more than 95 pitches in 13 of them.

“I knew my elbow was strong at the beginning of the year and I knew it’d be fine all year,” Zimmermann said. “I just thought I had a pretty good year.”

Johnson, after his first ejection since taking over the Nationals in late June, missed a wild finish. The Nationals used all seven relievers. One starter, John Lannan, reported to the bullpen in case the game went longer. Another, Livan Hernandez, dropped a sacrifice bunt as a pinch hitter in the 10th. As they hit in the 14th, some Nationals players on the bench turned their caps inside-out, Little League-style.

Storen entered the game in the ninth, the Nationals up 4-3 and three outs from victory, to face pinch-hitting rookie Yonder Alonso, who smashed a home run to right field on the second pitch.

“It’s a good pitch if I throw it over the outside part of the plate,” Storen said. “It caught the plate, and that’s right where his swing path is.”

The Nationals may have lost the game in the ninth if not for the cannon attached to Ankiel’s left shoulder. With one out, Dave Sappelt blasted a deep drive off the wall in right-center. Ankiel scooped the ball as Sappelt rounded second. He unleashed a missile that settled into third baseman Brian Bixler’s glove on one hop, nailing Sappelt.

“Right on the money, man,” Bixler said. “He’s got one of the best arms I’ve ever seen. You never know what’s going to happen when he’s got the ball in his hands.

The Nationals gave Storen that chance for the save with a late rally. Zimmerman, pinch-hitting with two outs the eighth, hit a line-drive single to right-center off Reds reliever Aroldis Chapman to drive in Danny Espinosa and knot the game at 3.

Ian Desmond led off the ninth with a single to right off Nick Masset, then stole second. Werth scored Desmond with a single up the middle.

The Nationals stranded 17 runners on base, seven in extra innings, including two when Desmond lined into a no-luck, bases-loaded double play in the 10th. The squandered chances allowed Votto to lead off the 14th. (“It’s too bad there was nobody in scoring position,” Johnson said. “We’d have walked him again.”)

Balester, pitching for the fourth consecutive game, threw Votto a 3-2 fastball over the outside corner. Votto “reached out,” Balester said, and roped the ball into the seats in left.

“He threw his best pitch and got beat by the NL MVP,” Desmond said. “It took a lot of guts for him to do what he did out there.”

The Reds celebrated and the Nationals retreated to the clubhouse. Most will have just Monday off. Zimmermann will wait until next spring, eager to take another step in his career.

“I just want to work hard this offseason and come spring training be ready to go,” Zimmermann said. “And pitch 200-plus innings next year.”