Mets first baseman Alonso crushed the 444-foot homer – the last of New York's runs – in Monday's victory.
The two teams traded scores until the seventh inning. The Marlins were the first to strike with a Starlin Castro two-run blast in the opening frame.
But New York answered in the second and fourth innings. Miami then plated another in the sixth to take a 3-2 lead. But, that would be the end of the Marlins crossing home plate for the day and the Mets took over from there in a showstopping top of the ninth inning.
Before Alonso's final blast, Juan Lagares - not known for his power or his offense in general - hit a game-tying home run. And starting shortstop Amed Rosario added an RBI in the ninth.
Setup man (and formerly the Mets closer) Jeurys Familia was awarded the win and Drew Steckenrider took the loss.
Steven Matz was the starter for the Metropolitans, giving up three runs - only one earned - in five 1/ 3 frames. That isn't the worst pitching line ever, Matz will need to improve from there a bit for the Mets to have a great season.
In the East: Kiermaier key to Rays win
Kevin Kiermaier went two for three with a run scored and four RBIs in the Tampa Bay Rays' 7-1 win over the Colorado Rockies. Tampa has had a surprisingly good start to their season with a 4-1 record and a +8 run differential.
And The Atlanta Braves bullpen threw five innings of scoreless relief in their 8-0 shutout of the Chicago Cubs. It was Atlanta's first win of the season. Welcome to the club, Braves.
Rockies Not Rocking at the Plate
The Rockies strung together six hits and only one run against the Rays. And three batters were 0 for four at the plate — Trevor Story, Ryan McMahon and Ian Desmond, while three more were 0 for three.
Meanwhile, Pittsburgh Pirates reliever Richard Rodriguez allowed two hits and three runs (two earned) without recording an out in his team's 6-5 extra-innings loss to the St Louis Cardinals.
Springer Springs One Over the Wall
Houston Astros outfielder George Springer accomplished a career first after sending a lead-off home run over the left-field wall. Springer started Houston's scoring in the first and they went on to beat the Texas Rangers 2-1.
The Astros, figuring to once again be among the best teams in baseball, have struggled a bit out of the gate with a 2-3 record.
Aaron Judge stretched out for this impressive catch during the New York Yankees' 3-1 victory against the Detroit Tigers. But the Yankees are currently suffering from a rash of injuries that include the biceps of Giancarlo Stanton as well as the strained shoulder of Miguel Andujar.
Monday's Full Results
St Louis Cardinals 6-5 Pittsburgh Pirates
Cleveland Indians 5-3 Chicago White Sox
New York Yankees 3-1 Detroit Tigers
Milwaukee Brewers 4-3 Cincinnati Reds
Baltimore Orioles 6-5 Toronto Blue Jays
Atlanta Braves 8-0 Chicago Cubs
Tampa Bay Rays 7-1 Colorado Rockies
New York Mets 7-3 Miami Marlins
Houston Astros 2-1 Texas Rangers
Oakland Athletics 7-0 Boston Red Sox
San Francisco Giants 4-2 Los Angeles Dodgers
Arizona Diamondbacks 10-3 San Diego Padres
Seattle Mariners 6-3 Los Angeles Angels
What's on Tap for Tuesday: Phillies and Nationals Duke It Out NL East Style
Tuesday will mark the first of 19 matchups between the Philadelphia Phillies, the current home of Bryce Harper, and the Washington Nationals - the former home of Bryce Harper.
Like your teenager before prom night, this game figures to have a LOT of drama.
How will the Nats fans react to seeing former star Harper? Will Harper help the Phillies keep their perfect record intact? How will Nationals ace Max Scherzer perform against his former team-mate? And why is the Phillies Phanatic like that?
To many of those questions, we'll soon know the answers. To the last one? The world may never know.
Did you know? LaLiga is back on today! Don't miss Atletico Madrid take on Girona or Villareal get on the pitch with Messi and the rest of Barcelona. Check today's full beIN SPORTS TV schedule here.