Bamboozled by Maroth's slow stuff, Green hit a leadoff home run in the 11th inning against Russ Springer to beat St. Louis 2-1 on Monday night in the Cardinals' first visit to Shea Stadium since winning Game 7 of the NL Championship Series last October.
"I haven't pulled a home run like that in a long time," Green said.
The Mets matched a season high with their fourth victory in a row despite getting only three hits. The NL East leaders won their seventh straight regular-season game against St. Louis overall.
Green connected for his seventh homer, sending a full-count fastball from Springer (3-1) off the scoreboard in right-center field. It was the Mets' first hit since Carlos Gomez homered in the third inning.
"When it got to 3-2, I felt he has got to throw a strike here. I figured he would throw me a fastball. I wasn't necessarily trying to hit a home run, I was just trying to drive one somewhere," Green said.
Green was hitless in three tries against Maroth, who did everything except win in his NL debut. "Maroth threw a great game and kept us off-balance," Green said.
"It was one of those days when I didn't feel like I had a lot when I went out there," Springer said. "I guess it was the first walk-off homer I've ever given up."
Minus the playoff drama and much action, the crowd of 40,075 had little to cheer for most of the night. The Mets went seven innings without a hit against Maroth and reliever Ryan Franklin while the banged-up Cardinals had ample soft outs, too.
Traded from Detroit to St. Louis last Friday for a player to be named, Maroth got off to an outstanding start in a new league.
"It's a little surreal," he said. "You like to make a good first impression."
Maroth quickly introduced himself to catcher Gary Bennett -- gesturing what each of his first eight warmup pitches would be -- and then shut down the Mets on two hits for 7 1/3 innings.
"I'm sure they didn't have much to go off of," Maroth said.
Throwing barely over 80 mph, he got Jose Reyes and others to take several awkward swings. Maroth helped himself by catching a pair of runners leaning the wrong way and picking them off first.
Maroth neatly slapped a single in a bunt situation -- injured teammate David Eckstein offered his bat before the game -- put down a sacrifice bunt and stole his first base in the majors. Maroth also did something equally rare, drawing applause from Mets fans when he exited during a double switch.
"After three or four innings, you should know what he's doing to you," Mets manager Willie Randolph said. "He's been a good pitcher in the American League. He knows how to pitch."
Mets starter Jorge Sosa pitched six effective innings against the team he finished up with last year. He spent the final two months with St. Louis as a reliever, was left off the postseason roster and still was rewarded with a World Series ring.
So Taguchi extended his career-high hitting streak to 17 games with a double and also had an RBI grounder that tied it at 1. Adam Kennedy opened the Cardinals fifth with a single off Sosa's leg for his 1,000th major league hit and later scored.
The Cardinals blew a second-and-third, none-out threat in the seventh, set up by Maroth's single and a daring double steal. Reliever Pedro Feliciano escaped the jam, retiring Scott Spiezio on a comebacker.
Missing injured Jim Edmonds, Chris Carpenter, Molina and Eckstein, these Cardinals hardly resembled the club that won at Shea last fall. Of the 25 players on St. Louis' roster for that NLCS, only 12 were active for this series.
"This team is no reflection of last year's team," said star third baseman Scott Rolen, who sat out because of a bruised left foot.
- Green hit his second career game-ending homer. The other came in 2001 with the Dodgers.
- Mets LHP Billy Wagner struck out three in two innings. He is now third among lefty relievers with 977 strikeouts; Jesse Orosco leads with 1,169 and Dan Plesac has 990.
- Albert Pujols made two errors at first base. He let loose a wide throw and dropped a low toss.
- RHP Troy Percival could join the Cardinals during the four-game series. Out of the majors since 2005, the former All-Star closer signed a minor league contract with St. Louis this month.