Pedro’s first start in a Boston uniform came against the A’s in Oakland on Opening Day, 1998. He fanned 11 in seven shutout innings in a 2-0 victory. The next day, the Red Sox sold 15,000 tickets for future games. Pedro's second start, at Seattle, was another masterpiece. By the time he returned to Boston for his home debut, the town was abuzz.  Pedro slowed down in May after getting slugged by an intestinal problem. Boston fans, feeling he lacked toughness, booed him and complained about his fat contract. They soon changed their tune. Pedro returned in June, battled through a tired arm down the stretch and finished with a 19-7 record and a 2.89 ERA.

in 1999, all the stars were aligned for Pedro to have his best year ever. From his first start to his last, he had it all working. In what ranks among the most remarkable seasons ever, Pedro went 23-4 with a 2.07 ERA—during a campaign that saw the most scoring since 1936. The league average ERA was almost three runs higher than Pedro's. The runner-up to the ERA title, David Cone, was at 3.44. Pedro whiffed 313, which not only led the AL, but made him the first pitcher ever to reach that plateau in both leagues.  Behind Pedro's stunning performance, the Red Sox managed to shadow the Yankees all year, but fell four wins short of a division title. Boston easily took the Wild Card, with a 94-68 record. The highlight of the regular season for Boston fans came at Yankee Stadium in September, when Pedro dismantled the Bronx Bombers with a 17-strikeout, one-hit gem. No one had ever struck out that many Yankees. A homer by Chili Davis accounted for New York’s lone tally.

Pedro also had a memorable appearance in the All-Star Game. In front of the faithful at Fenway, he struck out Barry Larkin, Larry Walker and Sammy Sosa in the first inning, and then fanned Mark McGwire to start the second. Matt Williams reached on an error, but Pedro struck out Jeff Bagwell and Pudge Rodriguez threw out Williams trying to steal. Another big day for Pedro was August 31, when he and his brother Ramon were reunited. The Red Sox had signed the older Martinez that spring, hoping he would recover from shoulder surgery in time to help them down the stretch. Ramon joined the club in time for the playoffs and won two games in September.

In the 1999 ALCS against the Yankees, Pedro started Game 3 and dominated again without his best stuff. He allowed just two hits and struck out 12 in seven innings, humiliating the Bronx Bombers 13-1. Sadly for Red Sox fans, that was their team’s first win of the series—and last of the year. New York had scored a pair of one-run victories to open the series and finished off Boston 9-2 and 6-1 to capture the pennant in five games.

The following season was an opportunity missed for Pedro and the Red Sox.  Laboring through shoulder soreness, he still pitched to a microscopic 1.74 ERA. No other starter in the league finished with a mark under 3.00. Pedro was tops in the AL in shutouts with four, strikeouts with 284, and batting average allowed at .167. His 18-6 record was the only thing keeping his team in the mix most of the campaign. Pedro, in his prime at 29, had full command of all his pitches and was just as tough on hitters when he didn’t have his 98 mph heater. His best game came against the D-Rays at the end of August, when he took a no-hitter into the ninth. Tamps Bay's John Flaherty broke up the no-no, which Pedro won 8-0.

The 2001 season found Williams under intense pressure. Unfortunately, the number-one man, Pedro, could not stay off the DL. After a great 7-1 start, he began to lose velocity in June and went on the shelf for July and most of August with a slight tear in his rotator cuff. It was an injury similar to the one that cut short Ramon’s career, though less serious.

Confident he could still dominate hitters without a mid-90s fastball, Pedro focused on doing whatever it took to give the Red Sox a complete season in 2002. There were no complaints about Pedro, who pitched great ball all year. He went 20-4, led the league with a 2.26 ERA and 239 strikeouts, and his .833 winning percentage was the best in baseball. Pedro's command was so good that he could put hitters away with any one of his pitches.

Boston's plan for 2003 was to plug holes. The offense carried the load for most of the year. Ortiz, Millar, Varitek, Ramirez, Garciaparra and Nixon each hit at least 25 homers, and Mueller edged New York's Derek Jeter for the batting title. Pedro contributed 14 wins and a 2.22 ERA in 29 starts.  The Division Series opened in Oakland. The A’s touched Pedro for three runs, but the Red Sox came back to take a 4-3 lead. Oakland tied it in the ninth and won in the 12th against Lowe. Back in Oakland for the decider, Pedro took the mound and hurled seven solid innings. The A’s led 1-0 going into the sixth, but Boston scored four times off Barry Zito. The bullpen held on for a 4-3 win to advance.

The Red Sox got their long-awaited postseason rematch with the Yankees in the ALCS. Wakefield won Game 1, but Andy Pettite beat Lowe the next evening to even the series. Pedro battled Roger Clemens in Game 3 at Fenway. With emotions running particularly high, he threw a bean ball at Karim Garcia, and the benches emptied. Pedro spotted Don Zimmer charging at him, sidestepped the Yankee bench coach, and tossed him to the ground. The incident enraged New York fans, as did a gesture Pedro directed at Jorge Posada. He pointed to his head, indicating that the Yankees catcher was next on his list. New York eventually got the better of Pedro with a 4-3 victory, but the fireworks didn't end. Clemens threw close to Ramirez as payback, and the Boston outfielder's overreaction created another fracas. Later in the game, Garcia hopped the right field fence and teamed with Jeff Nelson to pummel a member of the Boston grounds keeping crew.

Boston captured two of the next three to force a Game 7 in New York, with Pedro on the mound against Clemens again. The Red Sox chased the Rocket in the second inning, but Mike Mussina came in to control the damage. Pedro was up 5-2 after seven hard-fought innings. Little then made a fateful decision to send him out for the eighth. After Pedro retired Nick Johnson, hits by Jeter and Bernie Williams made the score 5-3. Little walked out to the mound and asked his ace if he had anything left. Pedro said yes and stayed in to face Hideki Matsui. He doubled, and the Jorge Posada did the same to make it 5-5. The Yankees won it in the 11th on a homer by Bret Boone off Wakefield. Little was fired 11 days later.

The 2004 season was played under the usual cloud of Yankee dominance.  Curt Schilling was now in the starting rotation, along with Pedro, Wakefield, Lowe and young Bronson Arroyo. Keith Foulke, the former Oakland closer, was signed to anchor the bullpen. The Red Sox went on a tear in September to give the Yankees a scare and wrap up the Wild Card. Pedro finished the year at 16-9 with an uncharacteristic 3.90 ERA. Still, he averaged better than a strikeout per inning, and hitters managed just a .238 average against him. Schilling, who went 21-6, became the Boston ace.

In the Division Series, Pedro got a win as Boston swept the Angels to set up another ALCS meeting with the Yankees. In Game 1, Schilling took the mound on a sore ankle and was beaten 8-7. Red Sox hopes faded further in Game 2 as Pedro lost 3-1. Game 3 was a complete embarrassment, as New York bombed Boston 19-8. The Red Sox stole Game 4, tying it against Mariano Rivera in the 9th and then winning it in the 12th on an Ortiz homer. Then it was all Red Sox, as Damon and Ortiz hit early homers and Lowe redeemed his so-so season with a great outing in a 10-3 win. It marked the first-time in post-season history that a team down 0-3 had come back to win it all. The World Series, between the Red Sox and St. Louis Cardinals, figured to be a hitter’s showcase. Pedro hurled seven shutout innings in Game 3, striking out six and retiring the last 14 hitters he faced. He escaped his only real trouble in the first when Ramirez gunned down Larry Walker at the plate on a short fly ball. The Boston outfielder, who hit .417 against St. Louis, was named the World Series MVP.

After Boston's World Series triumph in 2004, Pedro became a free agent and signed a 4-year, $53 million contract with the New York Mets.

Pedro was elected to the National Baseball Hall of Fame in January 2015 with 91.1% of the votes and had his #45 was retired at Fenway Park in July.