In a way, Liriano had the Cubs right where he wanted them.
Chicago began the night hitting just .218 with runners in scoring position, the second-lowest in the majors. The number dropped a bit more after Julio Borbon hit into a fielders' choice, Starlin Castro struck out and Anthony Rizzo flew out to right to end the threat.
No Cub made it to third base over Liriano's final four innings and Pittsburgh's bullpen made it hold up even with closer Jason Grilli given the night off after laboring through a 34-pitch save on Tuesday.
The Pirates improved to 26-0 when leading after eight innings while Samardzija's tough luck continued.
The right-hander has been lights out against the Pirates during his career. He came in 4-0 against them, including a dazzling eight innings of work in a 3-1 Chicago win on opening day.
Samardzija might have been even better this time around. His only miscue came in the first when McCutchen doubled with two outs and Jones followed with a single to right.
It turned out to be all the cushion Liriano would need. Tony Watson worked the eighth and Melancon — typically the setup man — came in for the ninth looking for his first save since Aug. 26, 2012, while playing for the Boston Red Sox.
The Cubs made him work for it. Soriano reached on strikeout-wild pitch and Wellington Castillo singled with one out. Nate Schierholtz and Darwin Barney both lofted weak fly balls to shallow right field that Pittsburgh second baseman Neil Walker corralled with ease.
NOTES: Chicago's Darwin Barney, who went 4 for 4 in the series opener on Tuesday to raise his average from .192 to .223, went 0 for 3 ... Pittsburgh's left-handed starters are 8-1 at PNC Park this season ... The series wraps up on Thursday. Jeanmar Gomez (2-0, 2.78 ERA) will make his first start against the Cubs. Edwin Jackson (1-6 5.76) starts for Chicago. Jackson is 4-1 with a 3.09 ERA against the Pirates in his career.