BOSTON -- Sandy Leon let Chris Sale handle the bulk of the workload for seven innings before taking matters into his own hands in the 12th.

Leon, who caught a masterful seven-strikeout performance by Sale in the left-hander's Red Sox debut, launched a walk-off, three-run homer in the 12th to send Boston past the Pittsburgh Pirates 3-0 on Wednesday night at Fenway Park.

"It started with Sale and then the relievers too just keeping the game with no runs, and then I got that home run the last inning," Leon said.

Jackie Bradley Jr. walked and stole second before Pablo Sandoval worked a walk to bring up Leon with one out in the 12th.

Leon launched an 0-1 fastball off Pirates reliever Anthony Bastardo (0-1) into the Green Monster seats in left field. It was his first career walk-off hit.

"I'm not a home run hitter, so I was just trying to get a base hit," Leon said. "Just trying to keep it simple, just get a base hit. ... The pitch was right in the middle."

Sale, acquired from the Chicago White Sox last December in the blockbuster deal of the offseason, was unable to get the win but looked sharp for Boston (2-0).

The five-time All-Star southpaw permitted just three hits and a walk over seven scoreless innings. The Pirates didn't have a runner past first the entire night.

"I'm not going to overcook this thing. Offensively they threw some good stuff at us," Pirates manager Clint Hurdle said. "Chris Sale's a quality pitcher."

Sale received a standing ovation on his walk back to the dugout after the top of the seventh.

"I appreciated it," Sale said. "I tried to go through my routine and do everything I usually do. But I tried to soak it all in at the same time."

Joe Kelly (1-0) earned the win with a scoreless 12th frame.

Dustin Pedroia was 1-for-4 with a walk and a strikeout and played his 1,400th career game, breaking a tie with Dom DiMaggio to move into sole possession of 11th place on the Red Sox's all-time games played list.

Pablo Sandoval, playing his 1,000th career game, was 0-for-4 with two strikeouts.

Jameson Taillon nearly matched Sale pitch-for-pitch in his season debut for the Pirates (0-2), giving up five hits and walking three while fanning six over seven innings.

"My biggest emotion is he worked quick and it was cold, so we probably fed off each other in that regard," Taillon said of Sale. "It was definitely a cool atmosphere."

Missed opportunities were the story of the night for Boston.

Singles by Bradley and Leon and a walk for Dustin Pedroia loaded the bases with two outs in the 10th for Andrew Benintendi.

Benintendi, who hit a three-run homer in the Red Sox's 5-3 win Monday on Opening Day, could only muster an inning-ending groundout to second this time around.

Several scoring chances were also squandered by the Red Sox in the middle innings.

Leon was thrown out easily at the plate by Pirates right fielder Andrew McCutchen to end the third inning after blowing through a stop sign rounding third on Pedroia's two-out single to right.

Mitch Moreland teased a homer on a deep fly to right with a runner on and two outs in the fourth, but McCutchen made the catch against the wall on the warning track.

"Very strong play with a throw and a good play going back to the wall, absolutely," Hurdle said of McCutchen, playing just his second career game in right. "Good to watch."

The Red Sox's best chance to break through came in the fifth, however, as they put runners on the corners with nobody out. Taillon impressively escaped the jam by getting Sandoval and Leon to strike out swinging and forcing Pedroia to hit a dribbler back to the mound.

"Having a fast heartbeat and freaking out is not going to do anything," Taillon said. "You've got to stay collected, try to execute one pitch at a time, see how many pitches in a row you can execute and get out of it."

NOTES: Boston RF Mookie Betts and OF/INF Brock Holt were out with flu-like symptoms. LHP Robbie Ross is dealing with similar symptoms and was a game-time decision. "It's been popping up all spring training. ... (We) quarantined a number of different players, but it's hanging around (the clubhouse)," Red Sox manager John Farrell said. OF Chris Young started in right field. ... Red Sox LHP David Price (left elbow strain) threw 25 pitches off a mound for the first time since his injury on Wednesday and will travel to Detroit. ... Pittsburgh's Opening Day payroll ($94.6 million) ranked 23rd out of 30 major league teams, per the Pittsburgh Tribune-Review. ... Pirates RF Andrew McCutchen homered off Red Sox LHP Chris Sale in high school and singled against him in the 2012 MLB All-Star Game, but he had never faced him in regular-season play before Wednesday. ... Pirates RHP Chad Kuhl opposes Red Sox LHP Eduardo Rodriguez on Thursday.