Rapid Reaction: Marlins 2, Mets 1 (20)

NEW YORK -- The New York Mets received the biggest scare of their season on Saturday as ace Matt Harvey had to leave the game with tightness in his lower back.

Then again, Saturday's game went so many innings that it's conceivable that Harvey healed by the time the game concluded.

Harvey's departure overshadowed what was a 2-1 loss in 20 innings against the lowly Miami Marlins at Citi Field. Adeiny Hechavarria had the go-ahead RBI single in the top of the 20th. The game lasted six hours and 25 minutes.

Saturday's game was the longest game ever at Citi Field, which opened in 2009. It's the Mets' longest home game since April 28, 1985, when they beat the Pittsburgh Pirates 5-4 in 18 innings at Shea Stadium, and longest game since they beat the Cardinals in St. Louis in 20 innings on April 17, 2010.

Harvey leaves: Harvey came out to start the eighth, but manager Terry Collins and trainer Brian Chicklo quickly joined him on the mound. Harvey was pulled soon after, and in the dugout he could be seen pointing to his lower back to pitching coach Dan Warthen.

Before leaving: Harvey, who was saddled with his fourth straight no-decision and eighth over his past nine outings, pitched well. He went seven innings, giving up just one run and striking out six. Miami has had success against Harvey this season, as he entered the game with a 4.35 ERA against them in two starts, but Harvey was able to get into an early rhythm. He remains undefeated (5-0).

Seen him too much: This is the fourth time the Mets have faced Miami starter Jose Fernandez, and he's pitched well against them all season. Fernandez is 1-0 with a sub-2.00 ERA against the Mets after surrendering just one run in six innings on Saturday.

Should have ended earlier: The Mets were 0-for-19 with runners in scoring position and left 22 men on base. They had multiple chances to win in extra innings.

Bad fundamentals: The Marlins need to go back to basics. In the fifth, they cost themselves a potential run when Fernandez's attempt at a sacrifice bunt instead turned into a fielder's choice. One batter later, Hechavarria was thrown out at home. In the eighth, a failed bunt by Juan Pierre resulted in Hechavarria being caught in a rundown, and then Pierre promptly grounded into an inning-ending double play.

Another loss for Marcum: Starter Shaun Marcum, who was supposed to pitch Saturday before the rainout on Friday, came into the game in relief in the 13th inning and picked up the loss despite an excellent appearance out of the bullpen. He went eight innings and gave up just one run on five hits, which is better than almost every start he's made this season. Marcum last started on May 31, and this marked just his second relief appearance of the season, both against Miami. On April 29, Marcum suffered the loss in Miami's 4-3 win in 15 innings.

Juan good day: Juan Lagares got it done both at the plate and in the field. His double in the second inning gave the Mets a 1-0 lead. In the fifth, with the score tied, he threw out Hechavarria at the plate to end the frame. Lagares hasn't been receiving constant playing time, as the Mets have opted to use Rick Ankiel, but Ankiel's lack of production might force the Mets to give Lagares a better look. He finished 2-for-8 on the day.

Up next: The Mets and Marlins will conclude this two-game set as Jon Niese (3-5, 4.40 ERA) will face Tom Koehler (0-4, 3.70 ERA) at 1:10 p.m.