Oakton junior R.J. Gaines already had four pitches in his repertoire when assistant Eric Gibbons approached him midseason about adding a cutter.

Gaines won’t overpower many hitters with his fastball, but by pitching to contact and mixing in curve balls, splitters and change-ups, the right-hander had earned a spot at the top of the team’s rotation. Within weeks, the cutter became a major part of his plan on the mound, and the results have only gotten better.

Relying heavily on his newfound pitch, Gaines went the distance in Wednesday’s 8-1 win over South County in a Virginia AAA Northern Region semifinal in Vienna. Every Cougar in the starting batting order reached base, and Gaines carried a shutout into the seventh inning, scattering six hits in a victory that clinched the team’s first state tournament appearance since 2007. Oakton advances to play Lake Braddock in Friday’s region final.

“It was hard the first few weeks to get it, but I got it down,” Gaines said. “It’s been really effective for me the last month and a half. . . . Whoever comes up, you’re going to get that ball.”

Coming off a pair of eight-run victories to begin the region tournament, Oakton (20-4) took its time heating up on Wednesday. The Cougars struck out five times in the first two innings before breaking out in the third.

The first six hitters reached base in the frame against South County (17-9), earning Gaines a three-run cushion. Senior Joey Bartosic (three hits) plated the first run with a double and later scored.

The Cougars went on to score at least once in each of the final four innings with senior Brian Burns and freshman Joe Rizzo each reaching base in all four plate appearances. Burns, one of 10 seniors on the roster, put an exclamation mark on the performance when he launched his third home run of the spring over the left field fence in the sixth inning.

“We can feed off each other,” said Burns. “It starts with one guy, and then we all just get going well.”

That was more than enough for Gaines, who only struck out three but managed to pitch around trouble. On a muggy afternoon, the hurler worked quickly, and his defense did the rest.

In the fifth, senior shortstop Mitchell Carroll saved a run with a fine play up the middle, spinning before the throw to first for the out. An inning later, Bartosic started a double play that killed another South County threat.

Gaines credited the cutter for helping him shut down the Stallions. The pitch allows him to keep the arm action of his fastball while generating movement. Although he’s just learned it, he said he’s become comfortable enough to throw it in nearly any situation, calling it “my get-me-out pitch.”

“The kid’s got a desire to be a good player,” Oakton Coach Justin Janis said. “Any time you have that, he’s going to try to do things to make himself better. He’s kind of picked it up and run with it.”

In the nightcap, third-ranked Lake Braddock blitzed Marshall, 16-5, on the strength of a 13-run fourth inning. Two days after eliminating top-ranked Madison, the defending state champion Bruins (21-4) trailed upstart Marshall (10-15) in the early going before blowing the game open with a parade of patient at-bats.

Down 4-3, Lake Braddock pounded out eight hits in the decisive frame, including a two-run double by junior Jack Owens, and also benefitted from four walks, two errors and a hit by pitch.

“We were tense, a little nervous, too,” said VCU-bound senior Alex Gransback, who reached twice in the fourth. “There was a lot of pressure on us, but after that inning, we were more relaxed.”

Marshall sophomore Mitch Blackstone had three hits, including a double and a two-run home run that staked the Statesman to the early lead.