Sosa's 603rd career homer was his first in July and he also had five RBI as the Rangers rallied and then held on for an 8-7 victory over the Seattle Mariners on Monday night.
"He has struggled in July and hopefully this is what is going to take to get him out of it," manager Ron Washington said. "We needed those RBI and he got them. I hope it's a trend that will happen from this point on."
Since a homer June 30 at Boston, Sosa was 6-for-43 (.140) with one RBI in 12 games in July.
The 38-year-old slugger finally snapped out of that slump with a two-run double in the third inning. Sosa's three-run homer in the fifth broke a 3-3 tie and put the Rangers ahead to stay.
"It's been a tough month for me. Every player has to go through that situation," Sosa said. "I know how hard I work every day and somehow, some way I'm going to get out of this."
It was Sosa's 15th homer this season -- one more than he had in 102 games for Baltimore in 2005 before sitting out last year. Brad Wilkerson also hit his 15th homer in the fifth, a two-run shot that chased Horacio Ramirez (5-3).
Kevin Millwood (7-8) won despite allowing 12 runners on eight singles and four walks in 5 1/3 innings. The first five Seattle hitters reached base, but the right-hander held on to improve to 5-2 over his last eight starts.
Jose Vidro was 4-for-4 with a walk and two RBI for the Mariners, who lost their third straight game since getting within a game of the AL West-leading Los Angeles Angels.
Seattle scored twice off Millwood before its first out. Then against Eric Gagne, the closer pitching in a non-save situation, the Mariners had four straight hits to start the ninth. Richie Sexson's three-run homer made it 8-7 before a game-ending double play.
The Mariners hadn't scored in 22 innings and were coming off consecutive shutout losses at Toronto in which they had only three hits in each game. They had three hits and a 2-0 lead against Millwood before their first out.
"We should have come out of the first with more runs," Vidro said. "It would have made a difference at the end. We were facing their ace. When you have him on the ropes like that, you have to go for the knockout."
Sosa played for the first time since being hit in the head by a pitch against Cleveland on Saturday night, when the Rangers honored him for his 600th homer before the game. Sosa became the fifth member in the 600-homer club June 20 in Texas against the Chicago Cubs.
Sosa also had a five-RBI game June 15 at Cincinnati. His 69 RBI in 82 games are ranked in the top 10 in the American League.
"For the most part, all year he's gotten big hits," Millwood said. "Give this team enough chances and keep them in the game, they're going to put some runs up more times than not."
Teixeira scored on a close play, reaching with his left hand to touch the plate on a feet-first slide at the same time catcher Kenji Johjima tagged him on the shoulder. Umpire Lance Barksdale immediately ruled safe, and repeated replays were inconclusive -- though Johjima was clearly surprised at the call.
"Lance said he slid around him. I thought he came up to call him out," manager John McLaren said. "It was a bang-bang play. I thought we had him."
Seattle got even in the fourth when Ichiro had a two-out single and a stolen base before coming home on Vidro's single. Vidro added an RBI double in the sixth.
Ichiro was 2-for-3 against Millwood, raising his average against the Rangers ace to .410 (16-for-39), the highest for anybody with at least 35 plate appearances. Vidro has the most hits off Millwood, two more Monday to push his total to 25.
- Ramirez is 5-0 with a 2.27 at home, but is 0-3 with a 15.22 ERA on the road.
- Texas reliever Akinori Otsuka, on the disabled list because of inflammation in his right forearm, made 15-20 throws off flat ground with no problems. He'll do it again Wednesday.
- The teams play a doubleheader Tuesday. They are making up a game that was rained out April 24.