Starlin Castro's RBI single in the seventh inning was all the run support that Jake Arrieta would need as the Chicago Cubs shut out the St. Louis Cardinals 2-0 Wednesday afternoon to return the favor that the Cardinals imposed on them on Opening Night.

Castro laced a 1-1 fastball from the Cardinals' Lance Lynn into left field to drive in Anthony Rizzo with the Cubs' first run of the new season. Rizzo had reached when Lynn hit him with a pitch. Lynn then overthrew first baseman Matt Adams while trying to pick off Rizzo,. The overthrow allowed the Cubs to get their man into scoring position.

Castro's line drive was just out of the reach of a leaping Jhonny Peralta at shortstop. Castro then took second on Matt Holliday's throw to the plate in attempt to cut down Rizzo.

The Cubs got their second and final run one out later. Chris Coghlan bunted Castro to third, and Miguel Montero brought Castro in with a sacrifice fly to the right-field warning track. Jason Heyward made the catch but had no chance to make a run-preventing throw.

Arrieta (W: 1-0, 0.oo ERA) pitched seven scoreless innings to pick up his first win of the season. He allowed just three hits while walking three and striking out seven. Hector Rondon (S: 1, 0.00) pitched a perfect ninth inning to notch the save.

Lynn (L: 0-1, 1.50) was the tough-luck loser. He allowed only two runs (one earned) in 6+ innings. He started the seventh and came out after Castro's RBI single. He allowed just two hits while walking one and fanning nine.

MLB.com's Carrie Muskat and Jenifer Langosch quoted Cardinals manager Mike Matheny discussing today's pitchers' duel and how the Cubs took advantage of Lynn's throwing error. Said Matheny,

"I think you just saw two very good pitchers throwing today, not making too many mistakes. And when there were, the opposition was able to capitalize."

Cubs catcher Montero added this in regard to the division matchup between the two teams: 

"You have to play good teams if you think you're going to win, and St. Louis is definitely a good team. You have to beat them to keep your hopes to make the playoffs. We did today, but we still have a long way to go."

Both teams will have a day off Thursday. On Friday, the Cubs begin a weekend series at the Colorado Rockies in Coors Field while St. Louis travels to Great American Ballpark to face the Cincinnati Reds.