Reynolds also totaled five assists and four steals, though had six turnovers. Taylor King made 4-of-8 three-pointers, ending with 20 points and nine rebounds for the Wildcats (9-0), who were coming off a win at Maryland on Sunday.
Antonio Pena ended with 15 points and seven rebounds in the victory, in which Villanova made 35-of-40 free throws.
Idris Hilliard had 22 points and seven boards to pace the Hawks (3-5), who have lost five of the last six against their rivals. Darrin Govens and Carl Jones scored 19 and 16 points, respectively, in the setback, the fifth in a row overall for Saint Joseph's.
Villanova held an advantage throughout the second half, with the lead at times reaching double-digits. But the Hawks never let the game totally slip away, and with a little over six minutes to play, Govens made two free throws and Jones followed with a three to bring Saint Joseph's within 73-67.
After two foul shots by Reynolds, Justin Crosgile drilled a three to make it a five-point game. The teams kept trading points down the stretch, and with two minutes left, Jones made three free throws to bring the Hawks within 84-80.
On the other end, King sank a long three-pointer to make it a seven-point game. A Jones turnover was followed by two Corey Fisher foul shots, which boosted the Villanova lead to 89-80 with just over a minute left.
Three foul shots from Crosgile got the Hawks within 95-89 with under half a minute to go, but Reynolds followed with two foul shots, as the Wildcats made 6-of-6 in the final minute to seal the victory.
King's layup capped a six-point burst midway through the first half to put Villanova ahead 29-20, and the Wildcats played in front until the Hawks used an eight-point run to take a 38-37 edge with under three minutes left in the period.
But Villanova got baskets from Reynolds and Maurice Sutton in the remaining time to take a 41-38 halftime lead.
A three-point play from Pena nearly five minutes into the second half sparked a seven-point burst that put the Wildcats up 57-47.
The teams continued to trading points, and two foul shots by Fisher made it 73-62 with just under seven minutes left.
The Hawks got 13 points and seven assists from Garrett Williamson, while Crosgile ended with 12 points...Fisher scored 13 for the Wildcats, who shot 46.6 percent....Villanova holds a 43-24 series lead over Saint Joseph's...The Wildcats' best start to a season was 13-0, achieved in 1937-38.