When he nailed Stephen Drew in the fourth inning on Saturday night, it was the fifth time he had thrown out a base runner trying to steal in 50 attempts.
In retrospect, it was a big play as the Nationals stretched their season-best winning streak to eight games with a 6-5 victory over the sloppy Arizona Diamondbacks.
Flores singled in the final and what proved to be the deciding run in Washington's five-run fifth inning. Jayson Werth and Michael Morse each had an RBI double and Ryan Zimmerman drove in two with a single in the uprising, a rally aided by two Arizona errors and a wild pitch by Diamondbacks starter Wade Miley (12-8).
"It was a mess," said Arizona catcher Miguel Montero, who committed one of the miscues. "It was a bad inning."
Flores is well aware that, while the Nationals have excelled in virtually all other departments, their failure to throw out runners attempting to steal has been a glaring weakness. Not that he is entirely, or even mostly, to blame, because Washington's starters are notoriously bad at keeping runners from taking off.
"I know people outside, they think different stuff," Flores said, "but it's been really hard for me being back there and not have the time or the chance to throw those guys out. Tonight I knew at any point that guy was going to take off. Even though it was a slider pitcher, I got a good release, and for the first time in a while, I got him out."
Edwin Jackson (7-7) got the win despite giving up five runs and eight hits in 5 2/3 innings.
"The runs we scored definitely backed up a bad outing by me," he said. "I guess it was just good enough to keep us close. The bullpen came in and did a good job, as always. We were able to get a win. It wasn't necessarily the way that I planned for it to go, but somehow it worked."
Tyler Clippard threw a perfect ninth for his 24th save in 28 tries.
The Nationals, with a major league-best 71-43 record, stayed 4 1/2 games ahead of Atlanta in the NL East. Arizona dropped five games behind first-place San Francisco in the NL West.
Miley went 4 1/3 innings, his shortest outing since June 30, and gave up six runs -- four earned -- and nine hits.
"It is very frustrating," he said. "You go out and the team gives you four runs, early. It is on me. I couldn't keep the lead. It got ugly out there. It was a merry go round and I couldn't put an end to it."
The rookie left-hander was cruising with a 4-1 lead when things fell apart.
Stephen Lombardozzi led off the fifth with a bunt single, took second on Jackson's sacrifice bunt, and scored when Werth doubled to right. Third baseman Chris Johnson couldn't handle Espinosa's sharp grounder, the ball careening off his glove into the outfield grass for an error that left runners at second and third.
Zimmerman followed with a single that brought home both runners to tie the game 4-4. Zimmerman took second on a wild pitch and advanced to third on the play when the catcher Montero threw wildly past second.
Morse's double brought in Zimmerman to put the Nationals ahead 5-4. Miley walked Adam LaRoche and was finished for the night, but the Nationals weren't.
While Washington had just one base runner, on a walk, in the final four innings, the Diamondbacks threatened in the seventh and eighth.
Hill led off the seventh with a double but Kubel struck out, then Paul Goldschmidt and Upton grounded out. Washington reliever Mike Gonzalez walked two of the first three he faced in the eighth. But pinch hitter Jake Elmore flied out in his major league debut, and Drew struck out.
The Nationals improved to 39-21 on the road, by far the best in the majors. ... With LHP Mike Zagurski designated for assignment on Saturday, Arizona has no left-hander in the bullpen. ... A serious dust storm swept through downtown Phoenix during the game, some sifting through the cracks of Chase Field. ... Washington improved to 10-2 in August, best in the majors. ... Miley is 3-4 in his last seven starts. ... A pair of left-handers go in the series finale on Sunday, rookie Patrick Corbin (3-4, 3.53 ERA) for Arizona, and Ross Detwiler (6-4, 2.99) taking the mound for the Nationals.