The 2009 season was the Mets' first at Citi Field. The team christened the new ballpark with a 70-92 won-lost record. They finished fourth in the National League Eastern Division.
The Mets began the '09 season with nine wins and 12 losses in April. In the season opener on April 6, they recorded a 2-1 win at Cincinnati. The Mets suffered a 6-5 loss to the Padres in the first Citi Field game ever on April 13. Two nights later, they chalked a victory in their new home for the first time with a 7-2 triumph over San Diego. The Mets ended a four-game losing streak by defeating the Nationals, 4-3, at home on April 24. The team closed the month with a pair of Citi Field defeats to the Marlins. The Mets stood four and one-half games behind the first-place Marlins.
The Mets got on to the winning track in May. The team won 19 games and lost nine during the month. From May 4 to May 10, the Mets had a seven-game winning streak. They went 3-4 on a west coast trip from May 14 to May 20. After winning two of three games in a series at Boston, the team had a 5-1 record on a month-closing home stand. The Mets had moved up to second in the N. L. East, one-half game in back of the front-running Phillies.
In June, the Mets season turned in the opposite direction. They had a record of nine wins and 18 defeats for the month. The team started June with four losses in six games at Pittsburgh and Washington. In each of their next four series, the Mets dropped two of three games. Between June 22 and June 28, they had three wins and four losses at Citi Field. The team ended the month with two defeats at Milwaukee. The Mets had fallen to two games under the .500 mark (37-39) and sat three games behind the division-leading Phils.
The Mets posted a 12-14 won-lost record for the month of July. The team went 2-3 on the road to start the month and followed with a split of six games against the Dodgers and Reds at Citi Field. Following the All-Star Break, the Mets won four and lost six on a road trip to Atlanta, Washington and Houston. They won three of four against the Rockies at Citi Field between July 27 and July 30. The Mets closed out July with a 3-2 loss to the Diamondbacks at Citi Field. Sitting in fourth place in the N. L. East, the team was ten and one-half games in back of the first-place Phillies.
August was another difficult month for the Mets. They won 10 games and had a .345 percentage for the month. The team started August with a 9-6 win over the Diamondbacks, but had a pair of three-game losing streaks between August 2 and August 8. At Citi Field from August 14 to August 24, the Mets suffered seven losses in eleven games. They ended the month with four defeats in six games at Florida and Chicago. The team had fallen to 17 and one-half games behind Philadelphia in the division.
The Mets concluded their inaugural Citi Field season with 11 wins in their final 31 games. The team began September by losing two of three games at Colorado. They went 2-4 against the Cubs and Marlins at Citi Field and followed with six losses in seven games at Philadelphia and Atlanta. The Mets went 2-4 at home against the Nationals and Braves from September 18 to September 23. They finished off September with a 2-4 record at Florida and Washington. The Mets then ended the year by sweeping a three-game series against the Astros at Citi Field between October 2 and October 4.