Buchholz threw a three-hitter to stop his string of seven starts without a win, leading the Boston Red Sox over the Rays 3-0 on Sunday.
Buchholz (6-8) walked none and struck out six. Only one runner reached second base during his second shutout this season and the sixth of his career.
"He was in complete command for nine innings," Boston manager John Farrell said. "Outstanding."
The right-hander's previous win came over Kansas City on July 18, five days after he tossed a three-hitter in an 11-0 win against Houston. He was 0-3 in that span.
"I felt good with all my pitches," said Buchholz, who threw just 98. "It doesn't always happen that way, but it's fun when it does."
Buchholz is the first Boston pitcher since Pedro Martinez in 2000 to have a pair of shutouts on three or fewer hits and no walks in the same season.
Alex Cobb (9-7) gave up two runs and seven hits over 6 1/3 innings and took his first loss in two months. After losing to Pittsburgh on June 23, Cobb went 7-0 with a 2.14 ERA in 11 starts entering Sunday.
"He had his 'A' game going today and when he's on like that, it's tough to scratch across runs," Cobb said about Buchholz.
Tampa Bay (66-71), which has been shut out 16 times this season, has dropped 10 of 15.
Xander Bogaerts singled leading off the third, went to third when Cobb was charged with an error for a wild pickoff try and scored to put Boston up 1-0 on Christian Vazquez's single. The Rays have at least one error in eight consecutive games for their longest streak since a team-record, 11-game stretch in 2004.
After Mookie Betts had an RBI single in the fifth, David Ortiz made it 3-0 when he went the opposite way against a defensive shift and hit a run-scoring single through the vacated shortstop spot in the eighth.
Ortiz has reached base in 16 straight games. He has 152 RBIs against the Rays, the most of any opponent.
Red Sox: 2B Dustin Pedroia was out of the lineup one day after leaving with concussion-like symptoms. Farrell said Pedroia is not expected to play Monday, but felt better Sunday and the team is hopeful the injury is a short-term issue.
Cuban outfielder Rusney Castillo, signed to a $72.5 million, seven-year contract last week, singled in his first professional at-bat and ended up 1 for 2 as the DH for the Gulf Coast League Red Sox in Game 2 of the GCL championship series. Expected to join the Red Sox in September, Castillo is scheduled to play three to five innings in center field in the final game of the GCL series Monday.
Struggling Rays OF Wil Myers was out of the lineup. The 2013 AL Rookie of the Year has just six hits in 42 at-bats, including 16 strikeouts, since returning from a broken right wrist that sidelined him for 70 games.
Red Sox RHP Rubby De La Rosa (4-5) and Rays LHP Drew Smyly (9-10) are the scheduled starters for the finale of a four-game series Monday. Last Wednesday night at Baltimore, Smyly became the second Tampa Bay pitcher to allow two hits or fewer over seven or more innings in consecutive starts.