The Phillies won hours after putting slugger Bryce Harper on the 10-day injured list because of a bruised left forearm.
Scratched from his previous start because of finger discomfort on his pitching hand, Velasquez (2-0) struck out five and walked three. The right-hander continued a solid May, lowering his ERA this month to 1.17 in four starts and one relief outing.
''I wasn't really trying to blow anyone away,'' Velasquez said. ''I tried to go deep in the game and have our bullpen come in and shut the door down. But at the same time if I'm in any type of jam, I'm not giving up,''
Phillies manager Joe Girardi praised Velasquez for his recent impressive stretch of outings.
''He's been throwing the ball extremely well,'' Girardi said. ''He's in a really good rhythm, he believes in what he's doing and just keep it rolling.''
Hoskins hit his 10th homer in the fourth, a two-run drive off Sandy Alcantara (2-4).
''It seems every time we face Sandy, that's A-plus stuff,'' Hoskins said. ''He's fallen into one of those categories, it's hard to give him a strike and work counts just by taking your pitches. If you get a good pitch to hit in the beginning of the at bat you've got to have a go at it.''
Hoskins' impact in the lineup will be vital now that Harper is out for an extended period.
''Everyone has to do the job and pick up the pieces,'' Girardi said. ''It can't be one guy but it's nice to have him really going at a time like this.''
Alcantara allowed only two hits in eight innings, and retired his final 13 batters after Hoskins' homer. The right-hander struck out four and walked one in his longest outing of the season.
''I'm mad at myself because that homer, I think I can make a better pitch,'' Alcantara said. ''I can do nothing about it.''
Sam Coonrod pitched a scoreless seventh and Jose Alvarado followed with a perfect eighth for the Phillies. Hector Neris got his eighth save, working around Garrett Cooper's two-out single in the ninth.
The Marlins loaded the bases with two out in the third before Velasquez ended the treat, retiring Jesus Aguilar on a line drive.
''We had pretty good at bats against Vince,'' Marlins manager Don Mattingly said. ''We just didn't seem to be able to string anything together. He seemed to get a little better as the game went on.
Jazz Chisholm's aggressive baserunning cost Miami two outs. Phillies catcher Andrew Knapp threw Chisholm out as he tried to steal third in the first, then center fielder Odubel Herrera's throw denied Chisholm's attempt to stretch a leadoff single into a double in the sixth.
PUMPED PHILLIES DUGOUT:
Hoskins' emotional display following his homer energized his teammates. The Phillies first baseman also said his reaction to the blast had a carryover effect the rest of the game.
''We played good baseball after that inning,'' Hoskins said. ''Whether or not, if it was sparked by that or not, remains to be seen. But the energy in the dugout was a lot better after that. Shoot, if it takes a little bit of emotion, I think all of us in that dugout are in.''
ACCEPT ONE BUT NOT THE OTHER
Mattingly had no issue with Chisholm's attempt to stretch his single but questioned his base-stealing attempt.
''The double (attempt) he was hustling the whole way,'' Mattingly said. ''The first one there was no real advantage in that there. That's one we talked about.''
Chisholm also rolled his right ankle on the failed double.
Phillies OF Roman Quinn was reinstated from the injured list. Quinn had been sidelined with a laceration to his right index finger.
Marlins: 3B Brian Anderson (partial left shoulder dislocation) was placed on the 10-day injured list and is expected to miss several weeks.
RHP Aaron Nola (3-4, 3.94) will start the third game of the series for the Phillies on Wednesday while the Marlins have not announced their starter.
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