Mets reliever Francisco Rodriguez wipes his face after giving up...

Mets reliever Francisco Rodriguez wipes his face after giving up a game-tying double to Washington Nationals' Adam Dunn during the ninth inning, Saturday. (July 3, 2010) Credit: AP

WASHINGTON - In what was supposed to be a showdown Saturday with Stephen Strasburg, baseball's newest pitching prodigy, the Mets turned out to be their own worst enemy.

On this particular afternoon, Strasburg wound up being a mirage, an empty promise of greatness that the patient Mets chewed up and spit out after five innings.

Instead, the real villain was Francisco Rodriguez, who for the second straight day was surprisingly ineffective - and this time, unlike Friday, he did not have Ruben Tejada to bail him out with a pickoff play.

Rodriguez was called on Saturday to protect a two-run lead in the ninth inning and slowly disintegrated, to the delight of what was left of the sellout crowd. K-Rod served up a tying two-run double to Adam Dunn that was an inch from being a grand slam, then allowed Ivan Rodriguez to deliver the winning single in the Mets' 6-5 loss to the Nationals.

"That was the worst performance I ever had in my entire life," Rodriguez said. "I should be ashamed, it's so embarrassing. I want to apologize to the fans that were watching that."

Thanks to Strasburg, K-Rod's meltdown was witnessed by a national TV audience, and it's a show the Mets have seen too much of lately. In back-to-back appearances, Rodriguez has retired only one of the eight hitters he's faced, and Saturday, the closer looked lost in suffering his fourth blown save in 23 chances.

"We have our issues," Jerry Manuel said. "We can't have an issue at the end of the game."

Rodriguez opened the ninth inning by walking pinch hitter Cristian Guzman on four pitches before getting Nyjer Morgan to ground out. The Nationals then loaded the bases with a base hit and walk before Dunn blasted a towering drive that kicked off the top of the wall in centerfield.

Angel Pagan later said he nicked the ball with his glove on the leaping attempt, and upon review, the umpires determined that it was a two-run double. But the score didn't stay tied at 5 for very long. Ivan Rodriguez punched the second pitch to rightfield to hand the Mets their 10th walk-off loss this season and third in only five days.

"It's tough, but what? Are you not going to run him out there the next time?" Jeff Francoeur said. "He's your closer."

Immediately after the game, Rodriguez already was looking at video of his performance, and pitching coach Dan Warthen sat with him at his locker to talk about some of the issues he saw. Warthen said K-Rod has developed a mechanical glitch that is messing with the command of his changeup and believes it is something that can be fixed fairly easily.

The Mets have done an excellent job of plugging their many leaks this season with a mix of rookies, such as Tejada, Josh Thole and Ike Davis, along with 30-something retreads such as yesterday's starter, R.A. Dickey (no earned runs in seven innings), and Hisanori Takahashi, who pitches Sunday.

Strasburg allowed two runs, four hits and three walks in five innings, striking out five, and was taken off the hook when the Nationals tied it at 2 in the sixth.

Tejada made a pivotal error in the sixth that opened the door for the Nationals to tie it, but he made amends with a sacrifice fly that helped the Mets build a 5-2 lead in the eighth. Thole did a superb job catching knuckleballer Dickey and also had two hits, including a single off Strasburg and an RBI double in the eighth.

But with the Mets' wobbly bullpen, they can't afford to have K-Rod plunge into a prolonged funk. Bobby Parnell gave back one run in the eighth on Adam Kennedy's RBI single. But Rodriguez has to be counted on to protect a 5-3 lead, especially against a Nationals team that had been 0-for-39 this season when trailing after eight innings.

Their last victory in that scenario? Last season, on Sept. 30, when Justin Maxwell crushed a grand slam off K-Rod in the ninth inning to give the Nationals a 7-4 walk-off win.

Said Warthen, "There's demons in this ballpark that he has to exorcise."