Verlander claimed his first-ever World Series victory in his ninth start with six strikeouts across five innings before Pressly's five-out save at Bank Citizens Park.
The Astros' defense came up big when it mattered too, with first baseman Trey Mancini making a huge play from Kyle Schwarber's low line drive to close the eighth inning, along with outfielder Chas McCormick leaping and holding a J.T. Realmuto shot on the wall for the second out in the ninth.
Houston go 3-2 up ahead of Game 6 at Minute Maid Park on Saturday, with the Game 5 winner when the World Series has been tied going on to win 30 of the previous 45 editions.
Jeremy Pena, who had three hits for the game, drove in Jose Altuve in the first inning, before Schwarber's leadoff homer over right field squared it up.
In the fourth, Pena blasted Phillies' starter Noah Syndergaard over Schwarber's head at left field for his fourth homer this postseason, becoming the first rookie shortstop to hit a blast in World Series history.
Alec Bohm's brilliant double play ended the Astros' ninth, but the Phillies were denied despite Bryce Harper getting on base for the fourth time in the game, with McCormick plucking a great catch before Castellanos hit to Pena who threw to Mancini to close it out.