PITTSBURGH -- The Royals’ weekend in Pittsburgh started strong but fell flat on Sunday with a 4-3 loss to the Pirates on Sunday at PNC Park.

Starter Brady Singer walked four and allowed four runs in five innings, while the Royals’ offense went 1-for-12 with runners in scoring position and left 10 on base -- the latter a continuing problem in the past few weeks.

“We needed to capitalize more,” manager Matt Quatraro said, “We drove up the pitch count early. We had baserunners in several innings and just couldn’t come up with the big hit to take the lead or break it open.”

The Royals still won the series this weekend and head home after a 3-3 road trip through New York and Pittsburgh. The final homestand of the year features matchups against the Tigers -- a team chasing the final AL Wild Card spot -- and Giants this coming week. Even with Sunday’s loss, the Royals have won seven of their past 10 games, and a postseason clinch is inching closer.

While they’re four games behind the first-place Guardians in the American League Central, the Royals still have a firm hold on the second AL Wild Card spot, 2 1/2 games ahead of the Twins in the third and final spot and a five-game lead on the Tigers, who are the first team on the outside looking in for the Wild Card picture.

But as the Royals eye October, Sunday exposed some concerning trends they’ll need to iron out over the next two weeks.

The first is hitting with runners in scoring position. Sunday was a winnable game, even with Singer’s command struggles. Pirates starter Jared Jones threw 97 pitches in four innings, forcing a bullpen that ranks fourth-worst in baseball in ERA (4.60) to cover five innings.

And the Royals have been one of the best teams in baseball this year hitting with men on base. Through Aug. 31, the Royals ranked first in batting average (.291), second in OPS (.826) and third in slugging (.468) with runners in scoring position.

“We certainly expect to come through in those moments,” Michael Massey said. “We’ve been good all year with them. … Any time you’re getting four, five relievers in the game, one of those guys is likely not to have it. You try to get deep into the bullpen. To their credit, they held up.”

But those RISP numbers have dropped off lately; since Sept. 1, the Royals rank 25th in baseball in average (.212), slugging percentage (.323) and OPS (.601) with RISP. On this road trip, they're 10-for-53 (.188) with RISP.

“I really believe in the volatility of that,” Quatraro said. “It’s not something that’s going to be steady all the time, hitting with runners in scoring position.”

Those numbers can be up and down for any team over the course of a season, but it stuck out immensely on Sunday.

Kansas City made it a one-run game in the top of the sixth when Bobby Witt Jr. walked with the bases loaded, but Salvador Perez’s flyout stranded three more runners.

After Yuli Gurriel’s sacrifice fly in the second with the bases loaded, two strikeouts ended the inning. Tommy Pham led off the third with a triple but was thrown out at the plate on Witt's fly-ball double play to right fielder Billy Cook.

“He made a great throw,” Quatraro said. “He put it up the line slightly, making it a really awkward spot to have to slide. The catcher did a good job of getting the tag down. That was a great throw. And you got to take your chance there.”

The Pirates took the lead in the fifth inning against Singer and never looked back. The righty struggled with his command and wasn’t landing his slider for strikes nor getting as much depth on it as he usually does.

Singer walked three batters in the fifth inning, including one with the bases loaded.

“I struggled to be competitive in the strike zone,” Singer said. “And I couldn’t really land the slider for a strike all day or get chase on it.”

A strength all season, the Royals' rotation has been especially excellent over the past nine games, with the starters going 6-0 and posting a 1.69 ERA across that span entering Sunday. But Singer wasn’t able to keep the momentum going, and he’s been in a tough stretch since the beginning of August, going 1-5 with a 5.40 ERA across eight starts in that time.

Kansas City has lost seven of Singer’s eight starts since August began.

“Not what I want to do,” Singer said. “I’m trying to give the team a chance every time I go out. Haven’t been able to do that lately. Just got to get back in the zone and trust my stuff.”