MILWAUKEE -- The Reds knew that to make the National League Central division battle a legitimate two-team race, they would need to sweep or win the three-game series over the first-place Brewers. After a 4-1 loss on Wednesday, it appears to be Wild Card or bust, as losses in the first two games leaves them trying to salvage Thursday’s finale.

Milwaukee (78-49) has a very comfortable, season-high-tying 9 1/2-game lead on Cincinnati (69-59), which has 34 games remaining in the regular season -- and one left vs. the Brewers. The Reds remained one game ahead of the Padres for the second NL Wild Card spot, likely their only realistic chance of getting into the postseason.

“We just keep playing. There is nothing else to do,” Reds manager David Bell said. “We’ve got a long way to go. Every game is going to be important. It’s a great time of year. We’re in good shape. We just have to keep playing like we always do and things will work out.”

Locked in a pitchers' duel against Brandon Woodruff, Luis Castillo gave his team every chance to win with 6 1/3 innings, allowing two earned runs on four hits and two walks, while recording six strikeouts. But hitters had their hands full trying to contend with Woodruff, who recorded 10 of Cincinnati’s season-high-tying 16 strikeouts over six scoreless innings.

“We had two stud pitchers tonight going. It was a good battle,” Reds shortstop Kyle Farmer said. “I think even though the score doesn’t show it, I think Luis outpitched him, honestly. He stayed in the game longer. His pitch count was lower than his. He pitched more innings. Luis is unbelievable. The way he manipulates the ball -- with his fastball and his changeup and then his slider -- has looked really good the past couple of starts.”

Castillo made the most of his changeup, which he threw 37 times out of 101 pitches. According to Statcast, he also generated eight whiffs out of 11 swings on his four-seam fastball, which topped out at 99 mph.

The Brewers were held hitless for the first three innings -- without a ball leaving the infield -- before Christian Yelich led off the fourth with a double to the left-field corner. Avisaíl García followed with an RBI double to the wall in center field to make it a 1-0 game.

“It was a slider right there,” Castillo said via translator Jorge Merlos. “I tried to do my best to locate it well and it just hung in the middle of the plate and he made contact on it. But that didn't stop me from competing the rest of the game and throughout the start.”

Having retired seven in a row through the sixth, Castillo opened the bottom of the seventh by hitting García with a pitch. Luis Urías reached on a one-out single out of the reach of a diving Farmer at shortstop. Jace Peterson then scorched a ground-rule double to left-center field that scored García.

“Today when I came to the ballpark, I said to myself, 'OK, we've got to win this game, we've got to win this game. We've really got to win this game,’” Castillo said. “That's how my mentality was when I went out there and pitched today, and I had a good outing, too. It didn't go our way, and we move on from here.”

The Reds' best shot at Woodruff was during the top of the first inning. Leadoff batter Jonathan India was hit on the left hand by a pitch, and remained in the game after a few moments of evaluation by the team's training staff. Tyler Naquin followed with a bunt single that extended his hitting streak to 14 games, but Woodruff retired the rest of the side in order to end the threat.

“I would say that Woodruff right there, that’s about as good of stuff as you’re going to have,” Bell said. “His fastball was dominant. To me, that was the game. That was the difference. It starts right there. We got something going there in the first and couldn’t get any runs across. After that, he just settled in.”

After Farmer’s leadoff single in the second inning, Woodruff struck out five in a row and retired 13 consecutive batters, which more or less set the tone for the evening.

Following Naquin’s second hit, a broken-bat single to right field in the sixth, Nick Castellanos fouled off six pitches before delivering a check-swing hit to the right-field corner. As Naquin reached third base, Castellanos was thrown out at second trying to push for a double, as a perfect throw from García beat him to the bag. The mini-rally ended when Joey Votto flied out to left field.

“That play changed the game. Avi’s defense tonight changed the game, period,” Brewers manager Craig Counsell said.

In the eighth, García burned the Reds one more time with a leaping catch at the right-field wall that robbed pinch-hitter Max Schrock of a home run. An inning later, with the Reds staring at a potential shutout, Castellanos lofted a one-out homer to left-center to finally put the Reds on the board, but it was too little, too late to change the outcome.