Marlins lefty Brad Hand, competing for the fifth starter spot, worked four innings, giving up five runs on five hits with three walks and three strikeouts.
Hand, who got his pitch count up to 76, entered Saturday's game having allowed two walks in eight innings. However, he had some issues throwing strikes, and the Mets made him pay.
In the second inning, Chris Young walked to lead off the inning, and the free pass set up d'Arnaud's two-out, two-run homer.
Chris Young doubled and stole third to open the fourth, and Hand walked Ike Davis. Flores then connected on his three-run homer to left.
Colon kept Miami off the board until the fourth inning. Giancarlo Stanton doubled to lead off the inning, and Garrett Jones delivered his second two-run homer in as many days.
On Friday in Kissimmee, Fla., against the Astros, Jones belted a two-run shot in the first inning.
The Mets tacked on two more runs in the sixth inning, opening a 7-2 lead off Henry Rodriguez. Flores delivered an RBI single and Colon ripped a run-scoring single.
Up next: Though Daisuke Matsuzaka appears to have the Mets' fifth starter's job all but sewn up, John Lannan and Jenrry Mejia will continue ostensibly competing for that job Sunday. Mejia will start a 1:10 p.m. ET game against the Nationals in Port St. Lucie, Fla., while Lannan heads to Orlando for a 1:05 p.m. game against the Braves. Both contests will air on MLB.TV.
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro. This story was not subject to the approval of Major League Baseball or its clubs.