In the first game, St. John's Neumann of Philadelphia overcame a seven-point deficit in the final three minutes to defeat Chambersburg, 63-62.
In today's action, Chambersburg and Providence face off at 5:30 p.m.; Neumann plays perennial national power DeMatha at 7; and the Gaels play Xaverian of New York City at 8:30.
Goretti (1-0) led by as many as 10 points early in the fourth quarter, but the Chargers' Brendon Rowell, who led all scorers with 24 points, hit three times from inside to tie the score at 59 with 2:33 left.
Dean Preston nailed a 3-pointer with 1:41 left for a 62-59 Providence lead. But following a missed free throw by the Chargers, Sowers drove from the left side for a layup to cut the Gaels' deficit to one.
Providence (0-1) had a chance to extend its lead with 15 seconds remaining, but Rowell missed two free throws and Goretti rebounded. Sowers was found open on the right side, and he calmly put through the game-winning shot. Goretti freshman Marcus Chung made one free throw for the final margin.
"We got down there and I knew I had to get the shooters in there," Goretti coach Cokey Robertson said. "Anthony made a nice move on that drive, then didn't hesitate on the jumper and buried it."
Kyle Logan had 19 points and Brad Runkles added 12 for Goretti. Marcus Oliver had 12 points for Providence.
Chambersburg (0-1) fell behind 39-26 with two minutes gone in the second half, but outscored Neumann 22-7 over the next six minutes to take a 48-46 lead after three quarters.
Brent Sollenberger scored on a layup, then followed with a 3-pointer to give Chambersburg its biggest lead, at 56-49, with 4:40 to play.
After a Neumann timeout, Chambersburg's Larry Johnson made a steal, but was called for traveling. The Pirates took advantage, getting a free throw from Victor Thomas and a 3-pointer from James Fowler to reduce the Trojans' lead to three points.
A three-point play by Thomas with 1:20 left pulled the Pirates to within one. After a Chambersburg free throw, Fowler hit another three to put Neumann (1-0) ahead for good.