Cliff Floyd and Carlos Beltran each hit grand slams in a franchise-record 11-run sixth to power the Mets to a 13-7 victory over the Cubs. New York took two-of-three in the series.

"It was a total nightmare," Cubs manager Dusty Baker said of the sixth.

Cubs starter Sean Marshall (5-8) served up Floyd's slam but the rookie should've been out of the sixth before that. With one out, Beltran was safe when Walker bobbled his grounder for an error. Carlos Delgado dropped a single in front of center fielder Juan Pierre, who got a late jump, and David Wright blooped a single to right to load the bases for Floyd, whose sixth career grand slam gave the Mets a 6-5 lead.

"I pride myself and my team on defense," Baker said. "You just can't give away runs."

Pinch-hitter Endy Chavez added an RBI single against Roberto Novoa before the Mets loaded the bases again, taking advantage of another Walker error on a botched double play. Beltran then launched his 26th homer of the season in his second at-bat in the inning. Wright added a two-run blast, his 21st. The Mets sent 16 batters to the plate in the sixth, and the Cubs threw a total of 70 pitches.

It's the first time ever the Cubs have served up two grand slams in the same inning, and fifth time in club history they've given up a pair in the same game. The last time a team had two slams in the same inning was April 23, 1999, when St. Louis' Fernando Tatis connected twice in the third inning at Los Angeles.

And it was tough for Walker.

"They always say this game will humble you at some point in time, and I was embarrassed to be out there today," Walker said. "I just didn't catch the ball. I've got a thousand excuses but nobody wants to hear them. Bottom line is I didn't catch either ball.

"I'm responsible for the 11 runs that inning," Walker said. "You can pin this game on me. I don't know what to say -- these fans have been so good to me and I go out there and do that and it's humiliating. I wouldn't wish that on anybody.

"You want to crawl in a hole and you have to go back out there for three more innings," he said. "That's the toughest thing in the world, and I've never had to face anything like that."

Was it a lack of concentration maybe?

"It wasn't concentration," Walker said. "I don't want to sit here and make excuses. Bottom line is I didn't catch the ball cleanly the first time and I didn't turn the double play."

"I've been there," Cubs catcher Michael Barrett said, empathizing with Walker. "I played third base. That's why I'm a catcher now. Whenever a teammate struggles, it hurts us all. They have a good lineup and they hurt us. They hit the ball well at the right time."

Phil Nevin, who hit a two-run, pinch-hit homer in the seventh for the Cubs, absolved Walker.

"It's not Todd Walker's fault," Nevin said. "C'mon -- sure he made a couple mistakes out there. It's not for a lack of effort. He didn't make the wind blow out and have a couple balls blow in the basket and things like that."

David Wright hit a two-run homer and Chris Woodward added a solo shot to go along with Floyd, who notched his 13th career multi-homer game. He led off the fifth with his eighth homer and hit the slam in the sixth in front of 40,157 fans at Wrigley Field on a sweaty 95-degree night.

The game had started well for Marshall. One day after Carlos Zambrano recorded his first career stolen base, Marshall had two hits, including his first career home run. He launched a 1-1 pitch from Mets starter Orlando Hernandez into the right-field bleachers to lead off the second, his fourth career big-league hit. He came into the game 1-for-11 with a single in the Minor Leagues in 2004 and '05.

"That's the best ball I hit all year for sure," Marshall said. "That's the first home run I've hit in a game. I never hit any over the fence in Little League. I made some good contact and helped myself out a little bit and it was fun."

The left-hander gave up seven runs, five earned, on seven hits and one walk over 5 1/3 innings. This was the rookie's 18th start, two more than he had all of last year in the Minor Leagues.

All he could do was watch as the sixth inning unraveled.

"It was a tough-luck inning for us," Marshall said. "They had scattered some bloop hits. It was tough to watch, but that stuff happens in baseball and you'll see it happen every day. Whoever minimizes the bad inning usually is victorious in the game."

Barrett hit a pair of RBI doubles, and Pierre had four hits to go along with Nevin's homer. Chicago did steal three bases in the game to raise the season total to 65. That matches the team total for the entire 2005 season.

This has been a year of weird firsts for the Cubs, and two grand slams in one inning can be added to the list.

"I've been saying this all year, but you've got to put those things behind you and move forward," Barrett said.

This story was not subject to the approval of Major League Baseball or its clubs.