CINCINNATI -- Pedro Martinez blew 'em away. Carlos Beltran knocked 'em in. Everything was going exactly according to plan for the new-look Mets -- until Adam Dunn exposed the one area they overlooked.

Dunn's second homer of the game tied it in the ninth, and Joe Randa followed with a solo shot off Braden Looper that sent the Cincinnati Reds to a 7-6 victory Monday in front of the biggest crowd in Great American Ball Park's history.

For the first time in their 129 season openers, the Reds finished one off with a homer.

"I felt like I was at a rock concert, screaming for the next song," said closer Danny Graves, who pitched the ninth and then piled on Randa at home plate. "We've had walk-off wins in the past, but I haven't had a feeling like this in a long time. It's the perfect script. I won't believe it until I watch it (on television)."

The Mets couldn't believe it, either. Not after the way Martinez and Beltran -- the cornerstones of their expensive offseason makeover -- performed in their New York debuts.

Martinez struck out 12 and allowed only one hard-hit ball -- Dunn's three-run homer -- during his six innings. Beltran had three hits, including one of the Mets' three homers, as they went ahead 6-3.

The Mets committed $172 million to those two players, giving the Yankees a run for their money when it came to making offseason headlines. Maybe they should have spent a little more on the bullpen, their weak link.

"I've been through this a lot," said Looper, who had 29 saves in 34 chances last season. "I've definitely given up my share of whatever you want to call it. But on opening day, it stinks. Pedro pitched a great game. He struck out the world."

One little corner of the world, anyway.

Martinez blew away the Reds and any doubt that at age 33 he can still dominate. After Dunn's first homer, he struck out 12 of his last 14 batters, making them look overmatched against his 94 mph fastball and nasty breaking ball.

Martinez became the fourth pitcher to amass 100 double-digit strikeout games, joining Nolan Ryan (215), Randy Johnson (204) and Roger Clemens (108). The crowd of 42,794 thought it could rattle him by taunting after his only mistake.

They should have known better.

Yankees fans tried it in Game 7 of the AL Championship Series last fall, mocking Martinez with a "Who's Your Daddy?" chant. Martinez had suggested the Yankees were his "Daddy" because they beat him so often.

The cheer didn't work at Yankee Stadium -- the Red Sox went on to their first World Series title in 86 years. It didn't work in Cincinnati, either, after Dunn's three-run homer put the Reds up 3-1 in the first inning.

All it did was get him pitching like the old Pedro.

"He gets a certain look on his face: That's it, I'm going to shut you down and that's it," said Willie Randolph, who lost his first game as manager of the Mets.

The fans broke into the "Daddy" chant while Martinez was in the process of fanning Randa to start his strikeout streak. He didn't allow a hit after the first inning and walked two before letting the bullpen take over in the seventh.

"Pedro was on top of his game," Randa said. "He was carving through us. He was unhittable. Once he was out of the game, there was a big sigh of relief on the bench. Crazy things happen on opening day."

Manny Aybar gave up Jason LaRue's RBI double in the seventh. Looper then let it slip away in only 14 pitches -- Austin Kearns' single, Dunn's homer and Randa's final swing. The third baseman raised his fist as he rounded first base, then got pummeled by his new teammates at home plate.

"I'll have to ice down my whole body," Randa said. "They beat me up pretty good."

Beltran hit a two-run homer off Paul Wilson, a former Mets No. 1 draft pick making his first opening day start at age 32. He also singled home the tiebreaking run in the seventh off David Weathers, one of three thirtysomething relievers brought in to shore up one of baseball's worst bullpens.

Beltran, Jose Reyes and Cliff Floyd had three hits apiece for the Mets. Kaz Matsui homered in his first at-bat -- the second straight year he's done that -- and Floyd hit a two-run homer off Kent Mercker in the seventh to make it 6-3.

Then, the bullpen got involved and the bottom fell out.

"It's not really frustrating," Martinez said. "It's too early to get frustrated. It was one bad inning, and the rest of the game was pretty good. I'm optimistic about it."

Notes

• Matsui, a six-time All-Star in Japan, homered on the first pitch he saw as a rookie last year, connecting off Atlanta's Russ Ortiz.
• Batting again in the NL, Martinez made contact in all three plate appearances -- a popup and two grounders.
• Ken Griffey Jr. singled though a shifted infield in his first at-bat, breaking his 0-for-12 streak against one of the few pitchers who make him look ordinary. He also walked and struck out twice.
• Griffey stays at seven homers on opening day, one behind Frank Robinson on the career list.
• It was Dunn's 10th career multihomer game.