How it happened: The game was scoreless until the 10th inning when Neil Walker went deep off Carlos Villanueva for a walk-off home run. Jeff Samardzija was brilliant for the Cubs, using just 89 pitches to get through seven shutout innings. Pirates starter Francisco Liriano was also stellar, striking out 10 and getting out of several jams. The Cubs blew several chances with men on and none out, while Chicago's Emilio Bonifacio was picked off in the top of the 10th on a call that was overturned by the umpires.
Key moments: There were several for the Cubs, two involving Anthony Rizzo. He struck out with two on and none out in the sixth against the lefty Liriano, and then popped out with a man on second two innings later with a right-hander on the mound. Earlier, Samardzija bunted into a double play that manager Rick Renteria challenged, but it was upheld after umpires saw the replay.
What it means: Samardzija retained his label as a big-game pitcher and became the first Cub since 1933 and '34 (Lon Warneke) to record back-to-back shutout appearances of seven innings or more on Opening Day. Samardzija was never in serious trouble, and in keeping his pitch count down he was able to last longer than Liriano. If that's the start of a trend for Samardzija, he'll take his game to another level. Rizzo gets somewhat of a pass considering that Liriano is as good as it gets when it comes to southpaws, but Rizzo was 0-for-3 with runners in scoring position, continuing a trend from last year.
Arrieta progressing: Cubs righty Jake Arrieta threw about 50 pitches on Monday morning as he recovers from a stiff shoulder that kept him out of spring training. He'll throw again in five days; the Cubs need to determine where he'll start a rehab assignment.
Vizcaino to Single-A: Cubs pitching prospect Arodys Vizcaino will start the season in the minors with Daytona because the Cubs want him in warm weather as he throws in game action for the first time in two years. Vizcaino had a good spring, hitting nearly 100 mph on the radar gun, but he is on a specific throwing program as he recovers from Tommy John surgery in 2012.