Buck Showalter admitted he was “impressed” with the way the Mets have manhandled his ace Randy Johnson, the favorite to win a second straight National League Cy Young Award.

The Arizona skipper is reluctant to say Johnson is “owned” by the Mets, but he does think the Mets now have a resounding advantage over The Big Unit.

“I would say it’s confidence,” explained Showalter after Johnson had his fourth consecutive disastrous outing against the Mets on Friday night.

“They are confident,” Showalter said. “A lot of players bring that into games [against Johnson] but few are able to carry that over [into success].”

The Mets, 13-3 winners over the Diamondbacks Friday night, are busting at the seams with confidence after absolutely crushing Johnson. The Big Unit lasted only 2 1/3 innings, surrendering six hits and six runs. He got the hook after Jay Payton doubled to right field to drive in two runs.

Johnson did not strike out a batter, the first time he has not recorded a “K” in an outing since April of 1989. The last time Johnson went just 2 1/3 innings was April of 1998. Prior to that, it was a two-inning stint in May of 1996.

With his 7.11 ERA, 22 hits and 0-2 record against the Mets this season, Johnson might even be passed over for Curt Schilling in Game 1 if the two teams meet in the postseason. Last year, in the Division Series, Johnson lost Game 1 to the Mets after allowing seven runs in 8 1/3 innings.

Friday night’s debacle dropped Johnson to 16-5 on the year and pushed his ERA from 2.30 to 2.41.

Johnson was understandably peeved after the game. He said he took “full responsibility” for the loss.

“I know this team has the capability to come back from every deficit,” he said. “But it’s tough when I give up six runs.

“I didn’t pitch well,” he said, stating the obvious. “Nothing worked.”

Johnson said he wanted to pitch right away again to “redeem myself” but acknowledged, “it doesn’t work that way.”

The Mets went into last night’s game with Arizona with a 5½-game lead in the wild-card race. With Atlanta winning also on Friday, the Mets did not creep any closer to the Braves in the NL East race, remaining two games back. The Mets and Braves play six times in September.

While Johnson’s pitches were not working, neither was his – or his teammates’ – defense. The usually-solid Matt Williams flubbed a short ball toward third and in his indecision to throw to first or to home, he fired high to catcher Damian Miller, allowing the second Met run crossed the plate.

In the third inning, Johnson dug himself in a deeper hole. With Edgardo Alfonzo at first after his second single of the game, Mike Piazza chopped a ball high over the mound. The 6-foot-10 Johnson easily and calmly fielded the ball, but spun and fired low and hard to second base and the ball skipped into center field.

Later that inning, Arizona right fielder Luis Gonzalez, also a solid defender, misread the ball off Payton’s bat and allowed the ball to fly over his head for a two-run double. Payton was Johnson’s last batter of the night.

The Mets are at a loss to explain their success against The Big Unit.

“There’s no way to figure that out, to tell you the truth,” Bobby Valentine said.

But Valentine, as well as several Mets, agreed Johnson did not have his best stuff. His fastball was several miles per hour slower than usual and Valentine even surmised that Johnson might have a blister, since he seemed to shy away from his breaking balls.

Showalter said Johnson’s velocity was only down “a little bit” and seemed to hint that Johnson was more peeved with the strike zone than anything else.

Payton, Alfonzo and Todd Zeile each had two hits against Johnson while Benny Agbayani worked two walks on eight straight balls in the second and third innings.

“It could have been a bad day for him,” acknowledged Agbayani, “But he was still throwing hard.”

Piazza went 0-for-2 against Johnson and said Johnson threw him good pitches.

While Payton said Johnson’s fastball – usually at 95 or 97 mph – was about 90 or 92, he said his breaking pitches were “pretty sharp.”

As for a psychological advantage?

“I don’t think any team is going to get in Randy Johnson’s head,” Payton said. “It’s a baseball gods thing. You just can’t explain it.”

Piazza admitted that baseball is a “psychological game” and that edges and advantages can turn in a heartbeat. “You just can’t allow yourself to get down mentally,” he added.