CHICAGO | The potassium-fueled Chicago Cubs?

Winning a pennant means fixing some longtime problems. Carlos Zambrano's low potassium levels, draining him of energy and prompting cramps in his right arm during the past two years, was one nagging situation.

No more -- at least on Sunday. Zambrano boosted his potassium count with an increased banana intake -- "too many bananas, " in his view.

The strapping right-hander allowed just two runs and no walks on just 105 pitches in seven innings for his first win in the Cubs' 3-2 victory over the Houston Astros.

"I feel like a monkey," a jovial Zambrano said of his recent bananas feasts.

"You ever see a weak gorilla?" Cubs outfielder Daryle Ward said of Zambrano's bananas cure, to go along with more water and less caffeine.

Most important for Zambrano was his control, which enabled him to stay in the game longer. His high pitch counts have shortened both his outings and overall effectiveness though he's won 16 to 18 games the past four seasons.

"The key is just pounding the zone, getting the first pitch over for a strike," Zambrano said.

Meanwhile, Derrek Lee hasn't needed a potassium boost.

He doubled in his first at-bat Sunday for his sixth consecutive hit going back to Friday's game. After being retired in the third and walking in the fifth, Lee slugged his third home run in the seventh off reliever Oscar Villarreal to break a 2-2 tie.

"It's funny, people said I was in a slump the first couple of games of this season," Lee said. "Now I'm (7-for-8). Baseball's not the NFL. We play a lot of games. There will be more peaks and valleys for me and every player during 162 games."

Soriano, still just 2-for-26, belted his first homer in the fifth. He also recorded his first assist of the season, throwing out speedster Michael Bourn at the plate in the first inning.

"I think even when I'm not hitting, I can help my team with my defense," Soriano said.

Carlos Marmol and Kerry Wood (save No. 3 and second in a row) retired the final six Astros in a row. Wood will be given the day off for today's game in Pittsburgh.