Javier Baez gave Chicago the lead for good Saturday afternoon with an RBI single in the fifth inning and added a run-scoring double during the seventh inning of the Cubs' 7-2 win over the visiting St. Louis Cardinals in the opener of a day/night doubleheader at Wrigley Field.

Ben Zobrist went 4-for-4 with two runs scored for the first-place Cubs, who have won two of the first three games of the five-game series and five of their last six overall. The Cardinals fell to 2-2 under interim manager Mike Shildt.

Baez's first RBI hit, the last of three straight singles to open the fifth, chased Cardinals starter Luke Weaver (5-9) and gave the Cubs a 2-1 lead. Kyle Schwarber followed with a sacrifice fly.

The tiebreaking hit put Tyler Chatwood (4-5) in line for the win despite another inefficient outing. Chatwood allowed only one hit -- Matt Carpenter's solo homer in the third -- but walked six while striking out just two over 5 1/3 innings. He now has more walks (79) than strikeouts (78) in 89 1/3 innings this season.

The Cardinals pulled within 3-2 on Yadier Molina's sacrifice fly in the top of the seventh, but the Cubs scored four times in the bottom of the inning, when Baez's double was followed by Victor Caratini's sacrifice fly and a two-run single by Tommy La Stella.

Baez finished with three hits; La Stella had two.

A quartet of relievers finished the combined two-hitter, with new addition Jesse Chavez pitching the last two innings in his Cubs debut.

Carpenter has homered in five straight games. During that stretch, he is batting .526 with seven homers and 11 RBIs.

Yairo Munoz had the Cardinals' other hit, a seventh-inning single.

Weaver allowed three runs on seven hits and five walks while striking out two over four-plus innings.

--Field Level Media