However, Soriano's celebration was shortlived. Part of his problems in the outfield have been because of a bad left knee. On Monday, Soriano will have an MRI to determine what's wrong.
"He's not moving good in the outfield and his knee is bothering him and it's tough," said Piniella, who may not play Soriano on Saturday.
The past three days, the knee has gotten worse, Soriano said, and whenever he puts any weight on it, the pain becomes more intense.
"I want to [get the MRI] to see what I have with my knee because it's not right," Soriano said.
It was obviously a problem in the Mets eighth. With the game tied at 1, Angel Pagan was safe on a double that dropped in front of Soriano, the second ball he misplayed in the game, but not the last. Pagan moved up on a sacrifice and Daniel Murphy walked, prompting Piniella to pull starter Ted Lilly.
Kevin Gregg (5-5) struck out Jeff Francoeur, but Fernando Tatis lined a double to left that Soriano tried to catch against the ivy-covered wall and missed. Pagan scored on the hit, while Murphy was thrown out at home.
"It was a very tough play," Soriano said. "I did the best I could to make that play. Thank God, we came back in the eighth."
Bradley doubled off Brian Stokes (1-3) for his third hit of the game to lead off the Chicago eighth, and scored one out later on Aramis Ramirez's single. Jeff Baker walked and Soriano fell behind, 0-2, in the count before launching his 20th homer off the third slider in the at-bat into the left-field seats. It was his first since July 29.
"I told him a few days ago that I'm really pulling for him," Piniella said. "One thing about him, he likes to play and he works hard and there's no quit in him."
Bradley, who has heard his share of boos at home this season, jumped to the top of the Cubs dugout and waved a towel to celebrate the game-winning hit.
"I was elated," Bradley said. "As much [stuff] as 'Sori' has had to take, and he goes out there playing on one leg and to come up big like that today, I couldn't be happier."
Lilly also cheered for Soriano, and held no grudges after the defensive misplays.
"I know that I'm going to go out there and have some games that aren't so good and my teammates don't get down on me," Lilly said. "They know I'm trying. It's not that easy. That's the thing -- if the guy is giving the effort, what else can you ask for?"
With the win, the Cubs avoided falling to .500, but won for only the seventh time in the past 21 games.
Before the game, Piniella said he felt as if he were 76, not 66. What about after the game?
"I still feel 76," Piniella said. "It hasn't changed one bit. It's nice to win a baseball game. Hopefully, this can get us on a little bit of a roll."