''For me, unfortunately, I'm going to take the blame on this loss because it's probably my fault,'' Wong said after committing his first two errors of the season in a 5-4 loss to the Milwaukee Brewers on Monday.
Wong walked three times and scored a run but hurt the Cardinals too much, with the errors leading to two unearned runs. It started with the first batter when he couldn't handle a routine grounder by Carlos Gomez.
''It was just one of those plays where it came off the bat funny, I took my eye off the ball a little too early and it got away,'' Wong said. ''I take pride in defense and this happening, I think it's something that has to bring me down to realize I still need to continue to work.''
Matt Garza overcame five walks to earn his first career win in St. Louis and Gomez had two hits and an RBI for the Brewers.
Wainwright (1-1) started his fourth opener at 10-year-old Busch Stadium and gave up five runs - three earned - in seven innings. Jhonny Peralta had two hits, including a two-run double off Jeremy Jeffress that cut the deficit to a run in the seventh.
''They had a good game plan,'' Wainwright said. ''They had a good game plan and they executed it in the big moments.''
The Cardinals were 2 for 13 with runners in scoring position, stranding 12 runners.
''We've had that a few games now,'' manager Mike Matheny said. ''It's early in the season, so I see it turning, but right now we're just kind of fighting to make something happen.''
Francisco Rodriguez earned his first save, helping himself with the defensive play of the game when he reached behind his head and snared Peralta's liner leading off the ninth.
Play was sloppy on both sides with Milwaukee shortstop Jean Segura also committing two errors.
Jeffress' wild pitch put both runners in scoring position ahead of Peralta's double, which got past right fielder Ryan Braun's attempt at a shoestring catch.
Segura doubled off the outstretched glove of new Cardinals right fielder Jason Heyward, who might have taken an indirect route to the ball, to set up Scooter Gennett's run-scoring groundout for a 2-0 lead in the second.
A double by Gomez that made it 4-2 in the seventh was the first RBI hit for the either team. Gomez made it a three-run cushion when he scored from second on Jonathan Lucroy's infield hit combined with Wong's wild throw to first.
Garza allowed two runs - one earned - in 5 2-3 innings to win for the first time in six career starts in St. Louis. He entered 0-2 with a 6.95 ERA.
Wainwright beat the Cubs in the season opener and had won six consecutive regular-season decisions since losing to Pittsburgh on Aug. 27.
The highlight of the pregame ceremony was a video memorial to Oscar Taveras, the promising outfielder killed along with his girlfriend in an automobile accident last fall. St. Louis uniforms include a patch on the left sleeve with the initials of the 22-year-old Taveras.
Cardinals favorites clad in red jackets rode atop convertibles during the traditional pregame procession around the warning track. Hall of Famers Bob Gibson, Lou Brock and Ozzie Smith led the parade that also included former managers Tony La Russa and Whitey Herzog.
Standing room attendance of 49,875 was the largest at Busch Stadium.
Garza's five walks in 5 2-3 innings were one off his career worst. Brewers pitchers totaled seven walks, fewest in the majors, their first six games.
Wong scored from first to tie it at 2 in the fourth when Segura overthrew first base going for a double play on a bunt by Wainwright.
Matt Carpenter was 1 for 12 against Garza before doubling to start the third.