Kansas City, Mo. ? The frustration is mounting for Mets manager Art Howe.

The usually calm Howe gave his players a closed-door lecture Saturday after New York blew two leads in a mistake-filled, 4-3 loss to Kansas City.

“I let them know I wasn’t really happy,” Howe said after the Mets’ season-worst fifth straight loss.

New York made base-running mistakes and failed to get down tags while wasting a fine outing by starter Al Leiter.

“Overall, we played one of our poorer games of the year,” Howe said. “We got what we deserved right there.”

Angel Berroa, who hit a two-run home run off Leiter in the second inning, singled into shallow right with one out in the ninth, and Wilton Guerrero took off from second.

Right fielder Gerald Williams made a strong throw to the plate but Guerrero was safe when catcher Vance Wilson had trouble handling the throw and tagged Guerrero with his glove while the ball still was in his other hand.

Berroa thought the runner would score.

“I saw the outfielder playing shallow. I was just trying to get the base hit,” he said. “It was close.”

It was more than close, an angry Wilson asserted.

“I think the umpire’s reply was that I didn’t have the ball. He was in a bad position if he didn’t see that I had the ball,” Wilson said. “The only replay I’ve seen is from behind and you can’t see it. But I had the ball right there in my bare hand. The guy’s out.”

Joe Randa, who had two doubles, singled leading off the ninth against David Weathers (5-3). Guerrero advanced to second on a sacrifice.

Jeremy Affeldt (2-3), who had converted nine straight save opportunities, inherited a 3-2 lead in the ninth but gave up a one-out single to Mike Cameron before Todd Zeile’s pinch-hit double tied it 3-all.

Kaz Matsui then hit a liner into left-center and Brandon Berger made a good running catch and easily doubled off Zeile, who was almost at home when Berroa tagged the bag.

“I don’t know what they were thinking,” Berroa said. “He went flying past me 100 miles an hour.”

It was the fourth double play for the Royals and the first time in seven plate appearances Matsui failed to reach base.

Mike Sweeney hit a tiebreaking RBI single in the eighth to put Kansas City on top 3-2.

Leiter, who hadn’t allowed a run in two starts since returning from the disabled list, went seven innings and gave up just two runs and three hits.

The Royals were hitless until Randa doubled leading off the fifth. Then Berroa hit the next pitch into the stands in left field for his fourth home run and a 2-all tie.

“I saw what he threw to Joe,” Berroa said. “So I thought I would take a chance and just jump on one.”

The Mets, who stranded 13 runners in a 7-5 loss the night before, got only one run after loading the bases with no outs in the first.

Mike Piazza drew a walk to force in a run, then Ty Wigginton lined into a 6-4 double play and Wilson grounded to first.

Cameron and Joe McEwing singled leading off the New York fifth and Cliff Floyd drove in a run with a groundout for a 2-0 lead.

Howe refused to say what he told the team after the game. Wilson did not care to talk about it either.

“I have no comment on Art Howe and what he said to us,” he said.

The Royals were victims of an unusual double play in the first. With one out and Carlos Beltran on first, Sweeney tried to check his swing. But the ball popped off his bat and went to first baseman Jason Phillips, who made a diving catch and then turned around and tagged the bag before Beltran could get back.

Royals starter Chris George failed to get a decision for the third straight start since being called up from Triple-A. He went six innings, giving up only four hits but also six walks and two runs while not striking out anyone. It was 2-2 when Brian Anderson relieved starting the seventh.

Notes: The Mets will wear the uniforms of the 1944 New York Cubans and the Royals will don the uniforms of the 1945 Kansas City Monarchs in a salute the Negro Leagues on Sunday. … Mets OF Shane Spencer missed his second straight game with a sore shoulder and was day to day. He pinch-ran for Piazza in the eighth. … Phillips made an outstanding sliding catch of Berroa’s pop foul in the seventh after Randa had doubled and been sacrificed to third. … The Royals lead the major leagues with 74 double plays.