"Casey has been rather clutch for us," Tampa Bay manager Joe Maddon said. "He seems to work a good at-bat, and obviously that was the turning point."
Kotchman's bases-clearing hit with two outs off Kyle McClellan (6-5) put the Rays ahead 3-1. Ruggiano followed with his fourth homer of the season to make it 5-1.
Tampa Bay, 20-21 at home this season, came in averaging just 3.1 runs at Tropicana Field, compared to 5.24 on the road.
Jeff Niemann (3-4) allowed one run and nine hits in six-plus innings. The right-hander had been 0-3 with a 6.65 ERA in his previous four home starts this year.
Tampa Bay designated hitter Johnny Damon moved past Boston Red Sox star Ted Williams, who had 2,654 hits, into 71st place on the all-time list with an opposite-field single to left leading off the first. Damon went 4-for-4 and has 2,658 hits overall.
"Ted Williams, to many, is the greatest hitter of all-time," Damon said. "Obviously, he could have had more hits. He walked so many times. Spent five years of (military) service to our country. Having the Boston ties that I do have and knowing the history of that franchise and the history of Ted Williams, it's a special moment."
Damon played four seasons with the Red Sox, including the 2004 World Series championship team.
McClellan gave up five runs and eight hits over 5 2/3 innings. He has lost five of his last six decisions.
"It's just a tough one to take," McClellan said. "It's disappointing that I let it happen."
Lance Berkman put the Cardinals up 1-0 with his 21st homer this season in the fourth. He had two homers in Thursday night's 9-6 win at Baltimore.
St. Louis, which had a four-game winning streak end, loaded the bases with one out later in the fourth but failed to increase the lead when Skip Schumaker hit into a double play.
Ruggiano made a nice sliding catch on Schumaker's foul ball down the left-field line with two on and two outs in the second.
"We actually did a terrific job of getting innings started and just didn't play good baseball," Cardinals manager Tony La Russa said. "Didn't do anything with it. We had some opportunties."
Tampa Bay beat the Cardinals for the first time at home after dropping the first four meetings in Florida, including a three-game set in June 2005.
The Rays wore the home uniform of the 1951 Tampa Smokers, a Class B Florida International League team, on Turn Back the Clock Night. The Cardinals used their 1953 road uniform.
La Russa said first baseman Albert Pujols, who broke his left wrist on June 19, could return ahead of time. The slugger was originally expected to miss four to six weeks. ... Kotchman had been hitless in his four previous at-bats with the bases loaded this season. ... Holliday (cold-like symptoms) was the DH for the second straight game and had one hit in four at-bats. He could play in the field Sunday. ... Schumaker singled in the seventh to extend his hitting streak to 11 games. ... Joe Paleveda, who played for the Smokers in 1946, threw the ceremonial first pitch. ... Tampa Bay granted right-hander Chris Bootcheck his release from Triple-A Durham after he exercised an out clause in his contract. ... The Rays acquired minor league right-hander Matt Torra from the Arizona Diamondbacks for cash considerations. He will report to Durham.