Top-ranked Holy Cross used its depth to overrun Immaculata, 80-52, and Melissa Mahony scored 38 points to lead O'Connell to a 60-59 overtime win over Keough of Baltimore in the opening round of the Georgetown Big Brothers Girls Invitational basketball tournament yesterday at Catholic University.

Annette Allor's eight points and Chrissy Reese's six paced a balanced Holy Cross attack that built a dominating 28-14 first-period lead.

Holy Cross was able to extend its advantage in the second period after Susan Castellan and Rita McNerney were benched for Immaculata with four fouls each. All 15 of Holy Cross' second-period points came from the foul line, Reese hitting nine of 11 attemps and hleping the Tartans to a 43-26 lead at intermission.

Led by Reese's game-high 21 points, Holy Cross had four girls in double figures. Sharon Geiglein typified the Tartans' bench strength, scoring her 10 points in the final period.

Mahony scored the game-winner for O'Connell with less than 20 seconds left in the overtime after O'Connell had built a seemingly secure 60-56 lead.

Keough's Cindy Sheridan then made one free throw and teammate Barbara Gray followed with a rebound basket to close to 60-50 with seven seconds to play. Dee Dee Sneeringer then stole the inbounds pass, but her shot at the buzzer bounced off the rim.

In regulation, Mahony sank two free throws with one second on the clock for O'Connell to knot the game at 54.