Giambi's three-run homer in the sixth inning was the key blow and the Indians broke a five-game losing streak with a 5-2 win over the Cincinnati Reds on Wednesday night.
Cleveland signed the 42-year-old veteran to a minor-league contract in February. Although Giambi is batting only .185, he has four homers and 16 RBIs in 65 at-bats. His latest home run stretched a precarious 2-1 lead and sparked the offense, which scored only 14 runs during the team's skid.
Justin Masterson (8-3) pitched six solid innings and worked out of a bases-loaded jam with nobody out in the sixth to preserve a one-run lead. The momentum carried over to the bottom of the inning when Giambi's homer off Bronson Arroyo put the game away.
Indians manager Terry Francona was the driving force behind signing Giambi, thinking he could contribute a couple of times a week and offer leadership to his teammates.
"When 'G' does something, everybody in there goes crazy," Francona said. "He's got a lot of fans in our dugout."
Although Giambi has been in the big leagues for 17 seasons, he's still approaching the game like a youngster. Earlier in the season, he won over his new teammates when he dove headfirst into first base to beat out an infield hit. Giambi hit a pinch-hit homer against the Reds on Monday to break an 0-for-24 slump.
"There's no greater feeling in the world to be able to contribute and help the ballclub out," he said. "It's exciting. It's what brings me back. Sometimes I wish I was still 25 or 26 years old, but unfortunately I'm not."
Cincinnati's only run off Masterson came on Joey Votto's two-out homer in the first. Mark Reynolds' homer to lead off the third tied the game before Nick Swisher's RBI double gave the Indians a 2-1 lead in the fourth.
The Reds took the first two games of the intrastate series with wins Monday and Tuesday in Cincinnati, but the Indians bounced back after losing seven of their previous eight. Cleveland's losing streak matched its longest of the season.
"We had a bad week," Francona said. "That's part of the season. I feel every bit as good about our club right now that I did 10 days ago -- maybe better because I've seen the fight they have in them."
Masterson, who has won four of his last five decisions, allowed four hits and struck out seven. Cincinnati loaded the bases with nobody out in the sixth, but Masterson worked out of the jam, getting Xavier Paul on a pitcher-to-home-to-first double play and retiring Devin Mesoraco on a fly ball.
"I was hoping to get a ball right at me, but you don't always get what you hope for," Masterson said of the double play.
Masterson also retired Votto on a groundout with two on to end the fifth.
"First of all, you have to have stuff to do it, but he competes so well," Francona said of Masterson's ability to work out of jams.
"Justin was tough over there," Reds manager Dusty Baker said. "That was their hottest pitcher, one of the hottest pitchers in baseball. He's always had good stuff, but he's really refined his skills."
Arroyo (5-5) retired the first two hitters in the sixth before Asdrubal Cabrera and Swisher singled. Giambi hit a 2-1 pitch to right for his fourth career homer in 21 at-bats off Arroyo, who gave up five runs in 5 2/3 innings. Giambi also doubled and is batting .381 (8-for-21) with eight RBIs lifetime against the Cincinnati right-hander.
"He's seen me a lot over my career, and he saw everything I had tonight," Arroyo said. "I knew he'd be in the lineup because Terry (Francona) knows about our history."
Cody Allen pitched a scoreless seventh and Joe Smith blanked Cincinnati in the eighth. Vinnie Pestano, who has taken over the closer's role for the injured Chris Perez, inherited a four-run lead in the ninth. He was greeted by Paul's leadoff homer, but retired the next three hitters. Perez was placed on the 15-day disabled list Monday with tendinitis in his right shoulder.
Arroyo has lost four straight against Cleveland, allowing 22 earned runs in 19 1/3 innings.
The teams exchanged solo homers early in the game. Votto, who is batting .417 (40-for-96) in May, hit a line drive to dead center in the first while Reynolds homered into the left-field bleachers in the third.
Cabrera doubled with one out in the fourth and scored when Swisher's hit found the gap in left-center, but the inning ended in sloppy fashion. The Indians hit three straight doubles but scored only one run when Swisher and Giambi on the basepaths.
Choo, who played with the Indians from 2006-12, made his first appearance in Cleveland since being traded to the Reds in December. He was 1-for-4 with a walk.
Cincinnati has lost eight in a row at Progressive Field. ... Reds RHP Homer Bailey (3-3) faces Indians LHP Scott Kazmir (2-2) in the finale of the two-game series Thursday at 7:05 p.m. ... Indians C Lou Marson (right shoulder) began a rehab assignment at Double-A Akron on Wednesday. He has been on the 15-day disabled list since April 25. Manager Terry Francona said there's no timetable for Marson's return but said, "It's probably weeks as opposed to days. He's been out for a long time now." ... Cincinnati bench coach Chris Speier is temporarily coaching third base while Mark Berry receives treatment for throat cancer. Miguel Cairo is the interim bench coach. ... Indians RHP Brett Myers (sore elbow) could resume his minor league rehab assignment next week. He has been shut down from throwing for five to seven days because of a recent setback.