After a Shannon Brady (28 points, 17 rebounds) layup with two seconds remaining in regulation for Scituate tied the game at 59 apiece, the Rockets started the overtime period on an 8-3 run, highlighted by 6 points (all from the line) from O’Brien, and never looked back, handing the Lady Sailors (24-1) their first loss of the season.

“We wanted [O’Brien] at the line and she wanted to be at the line,’’ said Reading coach Kim Penney. “She’s been steady for us all year. And today she did great when it counted the most.’’

The Rockets (24-0) will now play the winner of Wednesday’s game between Tyngsboro and Palmer at the DCU Center in Worcester on Saturday for the state title.

“Hats off to [Scituate] and their coach,’’ said Penney. “They’re a great team. We’re just very happy that at this point in the season we are playing a team that’s that good. This is what makes it so exciting. You don’t want to be here against someone that’s not going to challenge you. They more than challenged us, we had to play our very best basketball to beat them and that’s the best.’’

With 6:34 to play in the fourth and the Rockets trailing by 6, Olivia Healy (22 points, 10 rebounds, 7 steals) picked up her fourth foul, but Penney chose to keep her emotional leader on the floor. The move paid off, as the junior netted Reading’s next 5 points to bring it to within 51-49 with 3:49 to play.

Healy continued to dazzle, finding an open Katie Clements (6 points) for a 3-pointer to give the Rockets their first lead of the game, 52-51, with two minutes to play.

“I knew I just couldn’t foul out,’’ said Healy. “I was like, ‘Coach do anything but put me on the ball.’ ’’

With 20 seconds to play Reading had the ball up 1, 58-57. O’Brien took the inbounds pass and was immediately fouled. She went to the line and hit her first free throw, just after the referee’s whistle sounded to alert the players that a Scituate girl had fouled out.

The whistle negated O’Brien’s free throw, however, she hit her next attempt to put the Rockets up 2. Her second back-rimmed and the Sailors found Brady to send the game into overtime.

The Lady Sailors connected on their first five shots of the game, finishing the frame with a 16-14 lead.

Scituate started the second quarter on an 11-3 run, highlighted by senior forward Megan Otto (10 points, 5 rebounds, 5 assists), who was personally responsible for 5 of the 11 points. Her free throw with 3:30 to play before the half put the Lady Sailors up, , 27-17.

Reading started the third quarter off hot, as O’Brien and Healy both connected on 3-pointers and Melissa Liaboe scored 3 points the old-fashioned way to give the Rockets a quick 9 points.

However, an Otto 3-pointer gave Scituate a 7-point edge with 3:45 to play. Undeterred, the Rockets, led by O’Brien (12 points in the quarter), continued to grind away and entered the fourth trailing, 46-40.

“The first half we were doing a couple of things that we don’t normally do because we’d never seen a Shannon Brady, so we had to adjust,’’ said Penney.

“We’re finally proving to people that we’re here,’’ said Healy. “Reading’s here to stay and we’re going all the way.’’