AUGUSTA — Riley Robinson had a sore back, lungs that were worn out from their first real test after a dozen days resting that injury, and a fresh, four-inch abrasion tricking blood from beneath his left eye.

Winning, that feeling to which the Dirigo boys’ basketball program has become so accustomed in the past decade, makes everything feel better.

Robinson registered 14 points, 11 rebounds and three assists Monday afternoon, leading No. 2 Dirigo to a 51-44 Class C West quarterfinal victory over No. 7 Old Orchard Beach that was more grit than glory.

Dirigo shot only 14-for-47 (29 percent) from the field and committed 19 turnovers, but a second-half recommitment to rebounds and contributions up and down the lineup staked the Cougars to their 10th consecutive semifinal berth.

“I was pretty rusty, kind of tired out there. It felt great to be back at it with my teammates. I didn’t practice all week. Worst week of my life, probably,” Robinson said. “It was a physical game. I’m feeling good. It was a good win; a good team win.”

Clay Swett also delivered 14 points for Dirigo (17-2), which rides a 12-game winning streak into Thursday’s game against defending regional Waynflete at 7 p.m.

Gavin Hebert’s free throw tied the game at 24 entering the half, and the Cougars opened the third quarter with eight consecutive points to take command.

“They came out and kind of pushed it to 32-24 and got that seven, eight, nine differential, and that was tough to come back from,” OOB coach John Regan said.

Erik Hogan led the Seagulls (12-8) with 13 points. Evan Christensen added 11 points, nine steals and seven rebounds. Bryan Roberts scored eight of his 10 points in the fourth quarter.

OOB got it back to a four-point deficit, 34-30, on two Zach Hirst free throws. Swett, who had six points in the period, answered, courtesy off a nice feed from Robinson.

Dirigo went 11-for-14 from the free-throw line in a five-minute span of the fourth — five points from Robinson, four from Hebert and two by Kaine Hutchins — to put it away.

“It’s survive and move on,” Hutchins said. “They always give us a tough game. We’ve been lucky enough to come out on top most of the time, but they’re a bunch of tough kids, especially Roberts.”

The Cougars led 9-8 at the end of the first quarter despite shooting 3-for-16 from the floor.

Gavin Arsenault fashioned five of those points, capping the stanza with a 3-pointer from the left corner.

“They’re good defensively. They’re very physical. I didn’t know how quick they were,” Dirigo coach Travis Magnusson said. “Gavin Arsenault was really big for us offensively in the first half, making some passes, getting to the rim.”

Dirigo scored seven consecutive points, punctuated by Robinson’s 3-point play, to take a 23-15 lead with 3:29 to go in the half.

OOB roared back with a 9-0 run, begun by Christensen’s 3-pointer. Hogan’s steal led to two free throws. A putback by Joe Anderson and a Hirst pair from the line gave the Seagulls their last lead.

“We didn’t play our best basketball in the first half,” Robinson said. “We knew we could come out in the second half with energy. We were able to get the first (eight) points, get the lead, and it went from there.”

In addition to Arsenault’s seven first-half points, Tyler Frost contributed six points, three assists, and his usual array of floor-burn-inducing hustle plays. Hutchins had five points, six rebounds and three steals. Hebert threw in five points.

“They’re not all Riley. He gets a lot of the attention, and deservedly so, but they’ve got a lot of nice players, and they understand their roles,” Regan said.

koakes@sunjournal.com