Seth Miller joined the St. Stephen’s/St. Agnes boys’ lacrosse team as a sophomore in 2011 and jumped straight into the starting lineup.

At the time, Coach Andy Taibl didn’t have much choice but to toss the Potomac Falls transfer onto an attack weighed down by injury. Two years later, Miller has blossomed into the team’s most reliable offensive option, boosted by that trial by fire.

Miller lived up to that billing in Wednesday’s Interstate Athletic Conference semifinal at No. 3 Georgetown Prep, scoring the overtime goal that earned the seventh-ranked Saints a 7-6 win in North Bethesda. The Hofstra-bound senior scored four goals in all as his team completed a comeback victory to clinch its first appearance in the conference final since 2008.

St. Stephen’s/St. Agnes will travel to No. 4 Landon for Monday’s championship game, seeking its first title. The contest had been slated for Saturday but was bumped back to allow the Saints to play in the VISAA Division I tournament this weekend.

“He’s grown so much over the last three years of being here,” Taibl said of Miller. “He really is kind of the guy that gets our offense going. . . . He’s going to make his share of really good plays and some not-so-good plays, but you kind of just have to roll with them and trust him a little bit, at this point.”

Top-seeded Georgetown Prep (17-6) led 5-3 heading into the fourth quarter on Wednesday, only to allow three straight goals by St. Stephen’s/St. Agnes attackmen. Miller and juniors Jones Veith and John Aversa each scored to put the Saints (15-6) in front.

The Little Hoyas forced overtime thanks to a goal by junior Brendan Collins with 1:56 left, but never got possession in the extra period.

After the Saints won the faceoff, Taibl called timeout and drew up a play to get the ball to Miller. The attackman got possession behind the cage and raced around the crease for the game-winning score, his 61st goal of the season. (Watch video of the goal here.)

The IAC final adds another game for St. Stephen’s/St. Agnes in already jam-packed stretch. The Saints beat Flint Hill on Tuesday to earn a spot in their VISAA opener and will play Woodberry Forest in Friday’s semifinal round at Randolph-Macon College.

If they win that one, they’ll advance to Saturday’s final where they could meet No. 2 Paul VI before turning around to play Landon on Monday. The Bears won the regular season meeting, 4-2.

“It’s hectic and it’s busy, but I think most of the guys here are familiar with it,” said Taibl, whose team won the VISAA Division I title last spring. “They understand it’s just part of the deal. We just try to get the kids as rested physically as we can and mentally prepared for each game. Right now, they’re all elimination games, so you just take it one at a time.”

In the other semifinal, Landon knocked off Bullis, 6-3, in Bethesda to advance to their sixth straight conference final.

Senior Phil Pena scored twice and the Bears held the Bulldogs without a goal after halftime. Sophomore Hunter Sells made nine of his 11 saves in the second half.