SEATTLE -- Clay Buchholz felt exhausted after throwing only 76 pitches.
His return to the mound for the Red Sox after nearly a month on the disabled list was a test by an aggressive Seattle offense that had battered Boston pitching the first two games of the series.
"They made me work hard," Buchholz said. "I knew they were swinging. That's about the most aggressive team that I've pitched to in my career. For the number of pitches that I threw, that was a grinding, stressful outing, knowing I can't make a mistake."
Buchholz pitched into the eighth inning in his first start since late May, David Ortiz gave him cushion from the start with his 449th career home run in the first inning and Boston avoided being swept with a 5-4 victory over the Seattle Mariners on Wednesday night.
Outside of three batters in the second inning, Buchholz's return could not have gone much better. He was efficient, he pitched deep into the game to save Boston's bullpen and he relied on more than just two pitches.
Buchholz was using just his fastball and cutter early in the season. The time away allowed him to work on his curveball and changeup, and as his outing progressed, those pitches got better. Buchholz was so good with his pitch efficiency that teammates were questioning whether the count was correct.
"At one point I had to ask if the pitch count was right because it was the fifth and he had like 45 pitches," Boston catcher A.J. Pierzynski said. "It was good. It was an encouraging outing, and I'm glad for Clay that he went out and pitched like he did."
Ortiz knocked around Seattle starter Hisashi Iwakuma, plunking a two-run shot off the windows of the cafe in right field at Safeco Field for a 2-0 lead, his 18th home run of the season. He drove in another run in the third with a line drive off the wall in right that barely cleared the glove of Seattle right fielder Stefen Romero.
"I thought we had a very good approach against Iwakuma, who pitches very well in this ballpark," Boston manager John Farrell said.
Buchholz (3-4) was knocked around in the second, giving up home runs to Kyle Seager and Mike Zunino, but otherwise avoided problems. Buchholz retired 11 of 12 during one stretch and pitched out of trouble in the sixth inning when the first two batters reached on singles.
Buchholz won for the first time since May 2. He had been on the disabled list since May 27 with a hyperextended left knee and after two rehab starts in the minors was brought back to the Red Sox's rotation.
Buchholz went 7 1/3 innings, giving up seven hits and four runs. He struck out two and walked none. He might have gotten through the eighth but Brad Miller led off the inning with a homer.
"He looked confident, he looked relaxed," Farrell said of Buchholz. "He was able to make pitches with four different types of pitches. An overall outstanding performance."
Iwakuma struggled for the second straight outing, his pitches missing location. Iwakuma (5-4) lasted just four innings, giving up eight hits and five earned runs. Iwakuma was done when he failed to record an out after the first three batters of the fifth inning.
This wasn't the first time Boston has made Iwakuma's night short. Last season, Iwakuma lasted a career-low three innings, giving up eight hits and six runs against the Red Sox.
"I couldn't get the first-pitch strike, which cost me in a couple of at-bats," Iwakuma said through an interpreter. "They took advantage of that, so not being able to throw strike one got to me."
Ortiz is tied for 36th on the all-time home runs list with Jeff Bagwell and Vladimir Guerrero. ... Boston RHP Brandon Workman will start Friday's opener in New York against the Yankees. ... Seattle recalled RHP Brandon Maurer to work out of the bullpen. He was a starter earlier in the season.