ST. LOUIS -- Hunter Greene has found another gear over the past month, and the rookie starting pitcher's improvement has been eye catching. Not only are the adjustments visible in the big picture but also mid-game as well.

Greene largely shut down Cardinals hitters for five innings Saturday afternoon before Cincinnati's struggling bullpen let the game get away during a 5-4 loss at Busch Stadium that extended the Reds' losing streak to four games and seven of their past nine. It was a two-run walk-off home run by Tommy Edman against reliever Joel Kuhnel that stung the Reds.

"Their starter did a good job in the first few innings," Edman said. "He was tough, and we kind of just got better as the game went on and put together some good innings late in the game. And we just kept fighting, kept competing and doing our best to put together good at-bats."

Working into the sixth inning, Greene allowed one earned run on two hits and two walks with seven strikeouts.

Greene, who threw a seven-inning complete game Monday vs. the D-backs while retiring his final 20 batters in a row, struck out the Cardinals side in the first inning with three 98+ mph fastballs. But he also ran up his pitch count early in the process, with 43 pitches through two innings.

"I was a little sticky at the beginning, body-wise," Greene said. "I got a little bit more whippy at the end as I loosened up in my arm."

Greene started dialing in on hitters midway into his outing, including a 10-pitch third inning after the Reds scored three runs in the top half against Cardinals starter Adam Wainwright.

During his 1-2-3 fifth inning, Greene's four-seam velocity jumped especially as he struck out Yadier Molina. Molina fouled off a 101.7 mph fastball and whiffed on a 100.7 mph fastball for strike three.

"He’s doing a nice job of adapting as the start goes and adjusting to the hitters as they adjust to him," Reds manager David Bell said. "He’s pitching. We’ve seen that, really, most of the season now. It continues to be impressive.”

The course correction Greene has made overall provides a stark contrast.

• Over his first six starts, Greene was 1-5 with 7.62 ERA and 11 home runs allowed as opponents batted .291 with a 1.014 OPS.

• In his past six starts, Greene is 2-2 with a 3.18 ERA and four homers allowed -- none over his past three outings -- as hitters batted .164 with a .550 OPS.

"The importance of making adjustments, I think that’s one of the biggest points of being a professional," Greene said. "At this level, it’s being able to make pitch-to-pitch adjustments, not game-to-game. I’m taking pride in that, and it helps me put myself in a better situation to succeed. I’m not taking it for granted. I still have a lot of work to do and I’m continuing to find myself as a pitcher, which is super important. I’m really happy with these last few and looking to get better and better."

On a hot and muggy afternoon, Greene's elevated pitch count prevented him from extending into the later innings. Opening the sixth inning, Edman hit a single off Greene's foot and Nolan Gorman was hit by a pitch, the 101st of Greene's day.

Bad week for the bullpen
Bell went to his bullpen, which is now 0-3 with five homers allowed in the past eight games.

First, Alexis Díaz followed Greene and issued a one-out, four-pitch walk to load the bases. Tyler O'Neill almost hit a grand slam, but Nick Senzel made a nice catch at the warning track to limit St. Louis to one sacrifice fly.

Hunter Strickland gave up two runs in one-third of an inning in the eighth before Bell went to Kuhnel -- who pitched an inning Friday -- for a five-out save attempt. Kuhnel got a double play in the ninth but couldn't get the final out.

Tony Santillan was warmed up, but Bell stuck with Kuhnel.

“Absolutely I feel very responsible," Bell said. "It’s a big decision to leave Joel in there. He’s been pitching so well. He came in and did a nice job in the eighth to get out of that inning. Just threw a couple of pitches. Sent him back out but really, he pitched last night and pitched again today. To go back out, he faced a hitter or two too many."