MILWAUKEE -- The Nationals wasted a three-run lead in the eighth inning and lost to the Brewers, 5-4, in 13 innings on a home run by Gabe Kapler at Miller Park on Sunday afternoon.

With the score tied at 4 in the 13th, manager Manny Acta decided to go with right-hander Luis Ayala, who has been the Nationals' most inconsistent reliever this year. Acta had no choice, having already used four of his relievers in the game. Right-hander Steven Shell, the only pitcher left in the bullpen, had pitched two innings on Saturday.

Ayala didn't get the job done, as Kapler hit a 2-2 pitch over the left-field wall for the game winner and extend the Nationals' losing streak to three games.

"I was trying to throw strikes, make outs," Ayala said. "I threw my best pitch, the sinker. I didn't throw it where I wanted it."

Acta, who has seen Ayala at his best when they were both with the Expos, demands that everybody stays positive when things are going wrong. But even Acta couldn't deny that Ayala is having his worst season in the big leagues. Entering Monday's action, Ayala is 1-8 with a 6.04 ERA.

"It's very surprising. He has been struggling on and off -- now on," Acta said. "You can't even hide him right now. He comes out there in situations like this, and he is not making pitches."

Randy St. Claire has been Ayala's pitching coach his entire career. St. Claire has a clear picture what is wrong with Ayala. There are mechanical issues on the mound, but there seems to be more to the story. St. Claire believes that Ayala is putting too much pressure on himself because of his pending free agency after the season. Ayala most likely will not be back with the Nationals next season.

"Mechanically, he opens up early, and it puts him on the side of the ball," St. Claire said. "The ball comes the across the plate a lot on him. He pitches more with his offspeed pitches. It used to be 80 percent fastballs. He pitches now about 50 percent or less.

"I think he is putting some pressure on himself with his free-agent year. You're a professional athlete, and you have a contract coming up. You're a six-year free agent, and you are trying to impress people. You're thinking, 'I want to have a good year here.' So he's putting pressure to have a good year instead of focusing on getting the job done."

Ayala did not say if he was feeling pressured. He talked about moving past Sunday's defeat and concentrating on Monday's game.

"I'll come tomorrow and try to do my best," Ayala said.

It looked the Nationals had the game won after 8 1/2 innings. The score was tied at 1 after seven when Washington took the lead in the top of the eighth inning against reliever Eric Gagne.

After Ryan Zimmerman doubled with two outs, Austin Kearns hit the ball over the left-field wall for his sixth home run of the season to give Washington a 3-1 lead. Lastings Milledge then sent the ball over the left-center-field wall for his 12th home run of the season.

"When you go back-to-back like that [to] go up three runs, it pretty much a sealed deal with [closer Joel] Hanrahan coming in," Milledge said.

But the Nationals didn't seal the deal. The pitching staff had a season-high 13 walks, and two of them ended up hurting the Nationals in the bottom of the eighth. Right-hander Saul Rivera walked two batters and left the game with the bases loaded and two outs. Hanrahan came in and gave up a three-run double to Mike Rivera to tie the game at 4.

"Those walks ended up hurting us there," Acta said.

Left-hander John Lannan had his 17th quality start, but he ended up with a no-decision. He pitched six solid innings, giving up just one unearned run on one hit. By the time he left the game, Lannan had thrown 101 pitches and walked five.

Lannan had a no-hitter through 5 1/3 innings, but things started to unravel for him in the sixth. With one out and the Nationals leading, 1-0, Kapler hit a hard ground ball to Zimmerman at third base. Zimmerman made a great back-handed grab of the ball and made a good throw to first baseman Ronnie Belliard, but Belliard couldn't handle it and was charged with an error.

Prince Fielder walked and Corey Hart singled to load the bases, Bill Hall then came to the plate and hit a sacrifice fly to Milledge in center field to drive in Kapler.

"We all know Lannan didn't have his best stuff today," Acta said. "It's encouraging that this guy had a no-hitter going into the sixth inning without his best stuff. He ran his pitch count with those five walks, but we are so happy for this kid. We have a pitcher here. He has four pitches, and he can throw them for strikes."