BOSTON -- David Ortiz has been in the middle of some of Fenway Park's greatest moments. None of them seemed more important to "Big Papi" than his role in one Saturday afternoon.
Ortiz helped the Red Sox honor the victims and the survivors of the Boston Marathon bombings then played in his first game since last summer, a 4-3 victory over the Kansas City Royals capped by Daniel Nava's three-run homer in the eighth inning.
"I try to take the positive side of things and ride with it," Ortiz said, sitting at a table in an interview room. "But I wanted to win this game badly."
The Red Sox wore white home jerseys with "Boston" on the front instead of the customary "Red Sox." The shirts will be auctioned off for a fund to support victims of the bombings.
Kansas City players and staff wore a "B Strong" patch on the front of their jerseys. Neil Diamond sang Red Sox favorite "Sweet Caroline" before the bottom of the eighth.
"I think today was different because we haven't been through what we've been through this past week," Ortiz said. "Driving around and looking around at people's faces, it was a very emotional day here just looking at those guys that were injured by those bombs going off and watching the news nearly every day, it was painful, very painful. Today I could see people opening their chest and letting it go."
The 37-year-old Ortiz injured his right Achilles tendon running the bases on July 17 and appeared just once in Boston's final 72 games, against the Royals on Aug. 24.
Ortiz was bothered by inflammation in both heels during spring training and didn't play in any exhibition games. He was 2 for 4 in his return, tying the score 1-all with a sixth-inning RBI single off James Shields.
Following the emotional pregame ceremony, the Red Sox won their sixth straight game -- four since Monday's bombings at the marathon finish line.
"Knowing everything that went into the day for the city, for us to get the win, it came in a special way, special fashion," Nava said. "It made it all that more important."
Clay Buchholz (4-0) allowed eight hits in eight innings, struck out six and walked one. Andrew Bailey allowed Lorenzo Cain's leadoff homer over the Green Monster in the ninth, his fourth hit of the game, then got his third save when Alex Gordon hit a game-ending groundout with two on.
Cain went 4 for 4 with the solo homer, but it wasn't enough to slow down the hot Red Sox.
"Just a fantastic finish to an otherwise great day," Red Sox manager John Farrell said.
Cain even was moved by the pregame.
"It was electric, man," Cain said of the ceremony. "To go through that and see everybody getting into it and what this city went through, just to be a part of it was amazing."
Shields gave up one run and four hits in six innings with eight strikeouts and three walks.
Buchholz extended his scoreless streak to 22 innings before Cain doubled in the fifth and scored on Jeff Francoeur's single.
Cain doubled leading off the seventh and scored on Salvador Perez's two-out RBI triple for a 2-1 lead. But Jonny Gomes doubled against Tim Collins starting the eighth and Dustin Pedroia walked. After Ortiz grounded into a double play, Kelvin Herrera (1-2) walked Mike Napoli on four pitches and Nava homered to right.
Herrera said it was a poorly thrown change up.
"I left in the middle," he said. "I paid the price."
Cain is 11 for his last 16. ... Shields entered just 2-9 with a 5.86 ERA in his career in Fenway. ... Boston OF Shane Victorino left the game with lower back tightness. Farrell said he "twisted a little awkwardly trying to lay down a bunt." He'll be reevaluated (Sunday) morning. ... Boston's starters have allowed three or fewer runs in all 16 games this season.