But the Cubs' slugger heard some sporadic booing this week as he struggled in his comeback from a strained back. It happened again in the fifth inning Thursday after he lunged at an outside pitch and struck out for the second time.
When Sosa stepped to the plate in the 10th inning, he was hitting .210 since his return from the disabled list June 18 and was 1-for-12 with six strikeouts in the Houston series.
But Sosa turned everything around with one swing, powering a home run onto Waveland Avenue off Astros closer Brad Lidge on the first pitch of the 10th and giving the Cubs a 5-4 victory before a crowd of 39,116.
"I never doubted I was going to come back and help the team the way they want me to help," Sosa said. "It'll probably take a couple more games. Be patient, because I'm not going to do it every day."
Sosa was surrounded at the plate by celebrating teammates, who performed a group bunny hop with Sosa in the middle. Sosa now has five extra-inning walk-off homers, tying Ron Santo for the club record.
The Cubs wound up taking the series and moving within three games of first-place St. Louis in the NL Central as they prepared to play the White Sox on Friday in the city series rematch.
"If you lose this game, it's a downer going into the next series," Cubs manager Dusty Baker said. "It's a great emotional lift, especially winning a one-run game. They've been haunting us."
Carlos Beltran drove in all four Astros runs with two homers, including a game-tying three-run Waveland Avenue blast off Kent Mercker after Mark Prior left in the eighth inning.
Prior pitched well and departed with a 4-1 lead after giving up a leadoff double to Craig Biggio and walking pinch-hitter Mike Lamb.
But Baker brought in the left-hander Mercker to turn around the switch-hitting Beltran, who already had hit three home runs in the series batting left-handed, including one off Prior in his previous at-bat in the sixth.
"We were told by everyone in the American League, 'Don't let him hurt you left-handed, turn him around,'" Baker said.
Right-handed hitters were batting .178 off Mercker before Beltran's at-bat, so the strategy appeared sound. The execution, however, was lacking. Mercker left a fat one over the inside half of the plate on the first pitch and Beltran connected.
"I made a terrible pitch," Mercker said. "Mark pitched his butt off and I ruined it for him in one pitch. But that's the game. I'm not going to go and hang my head. I'm really glad we won. Sammy picked me up bigger than he knows."
Prior allowed three runs on five hits in 71/3 innings, striking out four and walking three. He blamed himself for "being behind in the count all day" but said he felt strong and made only four or five bad pitches in his 96-pitch outing.
Kyle Farnsworth pitched 11/3 scoreless innings, despite walking two, and rookie Jon Leicester improved to 2-0 with his second extra-inning victory and first since the 15-inning affair June 13 in Anaheim.
Leicester, whom Baker continues to put into pressure situations, showed his mettle again in the 10th after walking Lamb leading off. Up stepped Beltran, who was 6-for-12 in the series at that point with four homers. But Leicester retired him on a lazy pop to left and got out of the inning unscathed.
"I figure it can't keep going on," Leicester said of Beltran. "It's the law of averages."