Closer Edwin Diaz has been the main constant this season for the New York Mets, who begin a three-game series against the host Cincinnati Reds on Monday.

The Mets have struggled to score runs over the past week, but manager Buck Showalter knows the game is in control when he calls on Diaz.

The28-year-old was named as the National League's Reliever of the Month for June after allowing a run in 9 2/3 innings and converting all five of his save opportunities.

Diaz closed the door again on Sunday, when he recorded his 18th save with a scoreless ninth inning in the Mets' 4-1 victory over the Texas Rangers.

"He's so much more of a pitcher than I thought originally when I watched him from afar," Showalter said. "I know a lot of people think he just goes out there and sees how hard he can throw, but it's not the case. He pitches. And when you combine that with good stuff, you've got a chance to do what he's doing."

The Mets took two of three from the Rangers over the weekend and will be facing a Cincinnati club that recorded its first walk-off victory of the season on Sunday.

Albert Almora Jr. had two hits, including a bases-loaded single in the ninth, to give the Cincinnati Reds a 4-3 win over the Atlanta Braves.

The win snapped the Reds' four-game losing streak overall and a 10-game losing streak at Great American Ball Park.

"We're very aware that we haven't been winning as many games as we've been wanting to win," Cincinnati manager David Bell said. "I'm really happy with the resiliency today against a great team, one of the best in baseball."

The Reds will turn to rookie Hunter Greene (3-9, 5.72 ERA) for the series opener. Greene lost his second straight start last Wednesday, when he allowed three runs over four innings against the Chicago Cubs.

"He just had to work really hard, and they did a good job of not chasing," Bell said. "It wasn't like he was wild or anything. They had some really good, tough at-bats."

Greene, 22, will be eager to turn the calendar after going 1-3 with a 5.46 ERA in six starts covering 29 2/3 innings last month.

One bright spot for the right-hander was a dominant outing against the Arizona Diamondbacks on June 6, when he tossed seven shutout innings with eight strikeouts.

Greene, who is making his first appearance against the Mets, was selected by the Reds with the second overall pick of the 2017 draft.

New York will counter with right-hander Taijuan Walker (6-2, 2.72), who has recorded four straight quality starts.

Walker, 29, received a no-decision after pitching 7 1/3 scoreless innings with four hits, two walks and three strikeouts against the Houston Astros last Wednesday.

"I feel like I had everything working," said Walker. "We got a lot of soft contact, which is good, and the defense behind me was really, really good."

Mike Moustakas is hitless in seven at-bats versus Walker, who is facing Cincinnati for the second time in his career. He allowed five runs over five innings in a 7-0 loss to the Reds as a member of the Diamondbacks on July 8, 2017.