BRAINTREE - Sometimes, a 9-1 lead isn't enough to hold off the best teams that Division 1 baseball has to offer.

The Mansfield High School baseball team learned that painful lesson Thursday night in Braintree, losing to Boston College High School, 13-10, in the MIAA Division 1-South tournament's semifinal round of play.

The sixth-seeded Hornets (15-8) used the long ball to build the big lead, a grand-slam homer in the fourth inning by Chuck Erickson and a two-run blast by John Garabedian in the fifth. But the mound combination of Joe Swindells, Erickson and Bryan Saffelle could not tame the big bats of the second-seeded Eagles (19-4), who rallied for six runs in the bottom of the fifth and added six more over the course of the last three innings.

It was "smallball" that eventually did the Hornets in.

With Mansfield clinging to a 10-8 lead entering the bottom of the seventh, BC High's No. 9 batter, catcher Brendan Collins (3-for-4, two runs scored, three RBI) singled with one out. Tyler Horan drew a walk from Erickson and Rob McCunney singled home a run. After a strikeout, Nick Napoli's RBI-grounder was fielded at shortstop by Mansfield's Jim Gilmore, who saw that McCunney had overrun third base. He threw to Tom Savageau to get the Eagle in a rundown between third and home.

But as McCunney came to the plate, he appeared to raise his hands as if to interfere with the rundown throw. The ball was mishandled by Mansfield catcher Dan Gad and the second run scored on the play, putting BC High up 11-10.

"There was (interference), but they said the interference was actually on our catcher," Mansfield coach Tim Graham said. "It seems like a lot of calls went that way ... but that's not sour grapes. This one just hurts."

Swindells gave a sample of what was to come for most of the evening in the first inning. After giving up back-to-back singles to Horan and McCunney, the Hornet righthander (who threw 133 pitches through five-plus innings) got the next three batters (Billy Hocking, Napoli and Billy Kiley) on strikes to get out of the jam.

The Hornets loaded the bases with one out in the second on a single by Gad, an error on Mike Perillo's grounder and a walk to Greg O'Brien. Leadoff batter Shawn Doherty followed with a sacrifice fly to right to plate the first run of the game.

Another sacrifice fly tied the game in the bottom half, as Collins went deep to center field with the bases loaded and no outs to bring home Brandon Cipolla. Swindells got out of the jam with a called third-strike on McCunney and a grounder by Hocking.

Gad (4-for-6, three runs) doubled to left with two out in the third, and Savageau followed with a single to right to put Mansfield up 2-1. Perillo followed with a single, but Savageau was thrown out at third to end the uprising.

The Hornets chased BC High starter Jeff Rowan in the fourth as O'Brien singled, was sacrificed to third on Shawn Doherty's bunt, and Andrew Doherty and Garabedian drew walks. Rowan's day ended after 3 1/3 innings, six hits, four earned runs and 75 pitches.

Reliever Donny Murphy's day didn't start very well; Gilmore singled to right to bring home one run, then Erickson blasted the first pitch he saw in a majestic arc over the center field fence for a grand slam, putting Mansfield up 7-1.

Garabedian went deep with two out in the fifth, scoring Andrew Doherty (reached on an error when two infielders collided on his grounder) ahead of him to make it 9-1. Swindells had two out and one on in the fifth when the bottom fell out of his effort. Cipolla singled in Napoli, who had doubled, and John Micciche and Kyle Larrow reached to load the bases.

Collins poked a two-run single into left field, and Horan worked the count full before blasting a three-run homer over the fence to trim the Hornets' lead to 9-7.

Mansfield got a run back in the top of the sixth when Shawn Doherty walked to force home Gad, who had hit a leadoff triple. But the Hornets left the bases full in the inning, and when Hocking ripped a leadoff homer in the bottom half, that was all for Swindells.

It didn't help the Hornets' effort any that they hit into popup-throwout double plays to end threats in the seventh and eighth innings.

Savageau (3-4), Shawn Doherty (3-3) and Gilmore (2-6) contributed to the Hornets' 16-hit effort in a game that took three hours and 25 minutes to play.

Cipolla had four hits and Collins and McCunney three apiece for BC High, which will play fourth-seeded Catholic Memorial (18-5), a 6-4 winner over top seed Bridgewater-Raynham (20-3) in the first game, 7: 30 p.m. Saturday night at Braintree.

Mansfield 011 521 000-10 16 1

BC High 010 061 32x-13 17 3

Swindells, Erickson (6), Saffelle (8) and Gad; Rowan, Murphy (4), Cataldo (6) and Collins; W-Cataldo. L-Erickson.