BOSTON — Red Sox rookie Kristian Campbell capped off an eight-pitch at-bat in the third inning by drilling a 94.8 mph sinker from White Sox starter Jonathan Cannon to right field. It went for a two-run single that put Boston ahead 4-1.

The 22-year-old right-handed hitter went 2-for-3 with a walk and two singles to help lead the Red Sox 4-2 over Chicago here at Fenway Park on Marathon Monday.

“Just staying on the fastball, understanding what he wanted to do there,” manager Alex Cora said. “Got a pitch to hit. Hit it hard the other way.”

Campbell fell behind 0-2 in the count. He fouled off a sweeper, four-seam fastball and sinker and eventually worked the count full. Cannon missed middle of the plate on the eighth pitch and Campbell drilled it (105.2 mph off the bat).

“Try to be selective as possible and swing at the right pitches,” Campbell said. “Just try to be patient as possible.”

Boston also played the White Sox last weekend. And so he’s beginning to face major league pitchers a second time.

“We actually talk a little bit on the way home on the last (road) trip,” Cora said. “We talk about there’s an opportunity to face the same guys that he faced last week and to make adjustments and start looking for pitches. And the last two days, he has been impressive. Not chasing.”

Campbell said about making adjustments: “Honestly just starting to talk about it. Different teams attack differently to everybody. I literally just talk about it to the hitting coaches … and come up with an approach at-bat to at-bat. Just go up there with confidence and hit.”

Campbell entered Monday with a walk percentage (14.9%) in the 88th percentile among major league hitters and a chase percentage in the 66th percentile (24.7%).

Cora was even pleased when Campbell got called out on strikes in the fifth inning, the only time he didn’t reach base Monday. That’s because Campbell laid off a changeup below the zone that was called a third strike.

“The strikeout, that pitch was down,” Cora said. “We don’t want him to swing at that.”

Campbell has gone 24-for-76 (.316) with a .418 on-base percentage, .500 slugging percentage, .918 OPS, three homers, five doubles, eight RBIs, 11 runs, 14 walks and 21 strikeouts in 22 games.

“We had no doubts about controlling the strike zone,” Cora said. “His swing was all over the place in spring training. There was a lot of stuff going on, too. And now that he’s here, game-planning comes into play.”

Campbell said Fenway Park felt electric for Marathon Monday.

“To be a part of it for the first time this year is a big deal to me and a lot of people in this clubhouse,” he said.