On April 7, 1971, the Cardinals exploded for 12 runs through the first four innings of a 14-3 victory over the Cubs at Wrigley. Jose Cardenal and Joe Hague led the way in the 13-hit-attack with four RBI's apiece. However, nine of the Cardinals 14 runs were unearned, as the Cubs defense melted down behind their pitcher. They committed five errors before it was put in the books. While the Cardinals starter, Steve Carlton was touched for a couple of late homers it was a great start for the hurler who put the ghost of 1970 to bed by going the distance in the tilt. The '70 season was tough one for the big lefty, as he led the league with 19 losses, and only recorded 10 wins. He turned it around big time in '71, as he posted a 20-9 record, with the first of those 20 wins coming on that day in Chicago.
An article that was featured in the Southeast Missourian had Carlton attributing the strong performance to him shelving his slider. He had realized he had been hanging it, which led to the poor performance that had come the previous season. Carlton regained control of his slider as time marched on, however, he truly mastered the pitch in the City of Brotherly Love the following season after being dealt to the Phillies for Rick Wise in February of '72.
Check out the box score here: http://www.baseball-reference.com/boxes/CHN/CHN197104070.shtml