Daniel Descalso’s first career homer was a big one.

The scrappy 24-year-old third baseman slammed a three-run homer off Florida’s Clay Hensley in the seventh Tuesday, lifting host St. Louis to a 7-5 win.

Gaby Sanchez went 4-for-5 for the Marlins (18-10), who fell out of a first-place tie in the NL East. St. Louis (17-13) solidified its hold on first in the NL Central.

Sanchez, who belted a grand slam on Monday, singled in Hanley Ramirez in the seventh to put Florida up 5-4. But after Descalso’s blast, Jason Motte tossed a 1-2-3 eighth and Eduardo Sanchez closed for his second save.

Fernando Salas (1-0) pitched two innings to pick up the win. Ryan Webb (0-3), who walked Lance Berkman and yielded a single to Colby Rasmus prior to the Descalso blast, took the loss.

Major League batting leader Matt Holliday (.414) smashed his fourth homer, a two-run blast, in the first. He has 20 RBIs despite missing seven games following an appendectomy.