"It feels good," Lee said after hitting his major league-leading 32nd homer in a 6-5 victory Saturday over the St. Louis Cardinals. "But it was a huge game for us. We just have to find a way to put it together and keep it together."
The Cubs are 49-48 and in third place in the NL Central, 13 games behind the Cardinals.
"We've got to start winning eight or nine out of 10 to get into these playoffs," Lee said.
Jeromy Burnitz and Aramis Ramirez also connected, and Ramirez had three hits to help the Cubs end a three-game losing streak in 93-degree heat by beating an injury-ravaged lineup that featured only three Opening Day starters.
Albert Pujols was scratched with a mild left shoulder strain. But he drew an intentional walk as a pinch-hitter in the seventh ahead of Mark Grudzielanek's RBI single that cut the deficit to 6-5 and then stayed in the game.
Pujols called missing only his third start of the season a "miscommunication" after early batting practice and said his performance proved it.
"You didn't see me swing?" Pujols said. "I feel fine. Like I say, can you guys change the subject?"
Pujols' liner to shortstop with runners on first and second turned into a game-ending double play when Abraham Nunez was caught off second.
"I was just trying to think lucky," Cubs manager Dusty Baker said. "We haven't had many breaks here."
Besides Pujols, Scott Rolen (shoulder), Reggie Sanders (broken leg) and Yadier Molina (broken hand) are on the 15-day disabled list and Larry Walker (neck) was out of the lineup. Plus, rookie John Rodriguez, who has two homers in six games since replacing Sanders in left field, departed with a sprained right ankle in the third after doubling for the second time.
Rodriguez was injured when he tripped over an exposed nail in the dugout after the top of the third.
"Don't worry about me," Rodriguez said. "It's a one-day thing."
Still, the Cardinals have the NL's best record at 62-35 and a double-digit lead in the NL Central.
"Who cares about it?" Pujols said. "Nobody cares about it. We're winning with those guys out there, we're 11 to 12 games up and we don't have to worry about these guys playing the game hard."
Lee helped the Cubs win for only the 10th time in 43 games at Busch Stadium over the last six seasons. Lee is 11-for-31 during a seven-game hitting streak with five homers and nine RBI and is batting a major league-best .370.
The weather, to Lee's thinking, was even hotter than his bat.
"That's probably the hottest game I've ever played in," he said. "It was hot, hot, hot and humid. So it was a tough one."
His two-run shot off Matt Morris (11-3) with two outs in the fifth sailed over the visitors' bullpen in left before clanging off a guardrail, a drive estimated at 421 feet that put the Cubs ahead 5-3.
Morris gave up all three homers and was charged with six runs in six innings. He has allowed 10 homers this season after yielding 35 last year.
"Not much to say about it," Morris said. "I just made some mistakes, trying to go in on most of them, and just couldn't get the ball in."
Leadoff hits by Ramirez and Todd Hollandsworth in the second helped the Cubs take a 2-0 lead. Neifi Perez had a run-scoring groundout and Michael Barrett had an RBI single through a drawn-in infield that likely would have been a groundout otherwise.
The Cubs took a 3-0 lead on Burnitz's 17th homer in the third before the Cardinals, aided by second baseman Todd Walker's error, answered with two runs in the bottom half. Rodriguez's second double of the game produced one run and Walker's error on a routine grounder by John Mabry allowed pinch-runner Hector Luna to score from second.
David Eckstein, whose 11th-inning squeeze won Friday night's game, tied it at 3 with an RBI double in the third.
Cardinals pitcher Jason Marquis, who's batting .353 and leads major-league pitchers with 18 hits and nine RBI, struck out as a pinch-hitter in the sixth. ... The Cubs are 2-2 with four games remaining this season in St. Louis, where they haven't had a winning record since 1995. ... The crowd of 49,942 was the Cardinals' 13th straight of 40,000 or more.