When the fifth-ranked Rockville girls rushed ahead by 15 points early in the third period, Rams Coach Joan O'Brien knew the game was far from over. She was right.

Rockville promptly blew its big lead but regained its composure in time to earn a 60-58 decision in overtime over Montgomery AA rival Springbrook in a key game yesterday at Springbrook.

Springbrook (15-4), an early season 42-21 victor over Rockville, moved ahead, 54-52, in overtime before the Rams made three straight baskets to go up, 58-54. Holly Joyce, who scored all of her team's points in the extra session, cut the lead to 58-56. But Trang Pham got free and sank her second basket of the game to put Rockville ahead, 60-56, with 59 seconds left in overtime.

Joyce (14 points) scored again on a turnaround jumper with 15 seconds to play. Forced to foul, Rockville couldn't put the game away as Debbie Shockley (23 points), who sent the game into overtime with a leaning 13-footer, and Pam Goldsborough (19 points) each missed the front end of one-and-one foul situations in the final 26 seconds. But, fortunately for Rockville (16-1), it came away with the offensive rebound on each occasion.

"We finally calmed down and made a couple of smart plays," a relieved O'Brien said minutes after Goldsborough grabbed an offensive rebound and held on until the buzzer sounded. "Our press came back and we slowed them down. But I thought they would come back. They made their shots and came right back."

Rockville had things its own way in the first 2 1/2 periods. A full-court press completely unnerved Springbrook, forcing numerous turnovers that were converted into easy baskets. A 7-0 lead was stretched to 15-10 after one period, 31-18 at the half and 35-20 with less than six minutes to play in the third quarter.

Shockley, the premier girls three-pointer shooter in the area, had two long ones among her 12 points, and Goldsborough added 16 points in helping the Rams to their big lead.

Led by Joyce, Katie Sterling (20 points) and Lisa Richardson (10), the 16th-ranked Blue Devils stormed back. They outscored Rockville, 18-6, and trailed by 41-38 after three periods.

"We got out of control," O'Brien said. "They started making their shots and we took a couple of stupid ones."

The Blue Devils continued to force mistakes and finally eased ahead, 45-44, on a driving basket by Richardson with 4:44 to play in regulation.

The teams traded baskets until Sterling's jumper gave Springbrook a 51-50 lead with 29 seconds left. Rockville missed two shots on its ensuing possession, the second miss grabbed by Melanie Frye. She was fouled and made one of two free throws to increase the lead to 52-50 with eight seconds left.

But the Rams went to Shockley, who dribbled through three defenders, leaned in and tossed up a jumper just inside the lane to tie the game with one second left.