Fans had to wait out a 10 minute late start due to weather.
Pirates starting pitcher Francisco Liriano in the first inning.
Pirates pitcher Mark Melancon came on in then ninth inning to close the game as the Pirates won 1-0 over Cubs.
The Pirates' Andrew McCutchen flashes a sign after hitting a double against the Cubs in the first inning.
The Pirates' Starling Marte gets a hit in a 1-0 win over the Cubs.
Pirates manager Clint Hurdle gives a pat to Andrew McCutchen after he scored the only run of the game against the Cubs in the first inning.
By Michael Sanserino Pittsburgh Post-Gazette
Francisco Liriano said he worked hard this offseason to perfect a tweak in his delivery. Manager Clint Hurdle said he has watched a lot of tape and still can't see a difference.
The difference in the results, however, is undeniable.
Liriano has been dominant this season and continued that early trend by striking out nine batters in seven scoreless innings to lead the Pirates to a 1-0 victory against the Chicago Cubs Wednesday night at PNC Park.
Since returning from the disabled list May 11, Liriano is 3-0 in three starts. He missed the first month and a half of the season after fracturing the humerus bone in his right, non-throwing arm in December.
He allowed two hits and walked one Wednesday night in his sharpest outing.
Pirates vs. Cubs, 12:35 p.m., PNC Park.
Root Sports, KDKA-FM (93.7).
RHP Jeanmar Gomez (2-0, 2.78) vs. RHP Edwin Jackson (1-6, 5.76)
Jackson vs. left-handed hitters, who are hitting .326 with a .420 on-base percentage and a .416 slugging percentage against him this season.
As a starting pitcher this season, Gomez has a .197 batting average against him while allowing four home runs in 18 2/3 innings.
Liriano credits his improved command with a change he made in his throwing motion this offseason, moving his arm slot closer to his body and throwing the ball over his head.
"I'm just going over my head and not trying to overthrow," he said.
"Sometimes, I overthrow when I get into trouble. Other than that, I'm just trying to hit my spots. That makes the difference, right there."
Liriano has posted a 1.00 ERA in 18 innings, striking out 25 batters -- a rate of 12.5 strikeouts per nine innings. His command, a concern entering the season, is much improved.
"When he gets ahead with his fastball and he's close to the plate with his fastball, his other stuff plays up dramatically," Hurdle said.
Liriano deftly commanded the strike zone while cruising through the Cubs batting order, striking out at least one batter every inning he pitched. He threw 91 pitches, 59 for strikes.
"When he's had fastball command, those are the games that are electric for him," Hurdle said.
The Cubs' Jeff Samardzija, was nearly as brilliant. The tall right-handed pitcher struck out eight and allowed one earned run on three hits over seven innings. But that one run was enough to beat him and the Cubs with Liriano on the mound.
Samardzija always has pitched well against the Pirates, entering the game with a career 4-0 record and 0.92 ERA in 14 appearances, three of them starts.
In his previous start against the Pirates on opening day, he allowed two hits over eight scoreless innings.
This time, Samardzija (2-6) threw 111 pitches, 73 for strikes. He walked one.
With the victory, the Pirates (28-18) are 10-2 in their past 12 games.
The Cubs (18-27) have lost four of their past five and five of their past seven games.
Garrett Jones drove in the only run in the first inning, his team-leading 25th RBI this season.
Jones hit a line drive single to the right-center field gap, scoring Andrew McCutchen as the Pirates took a 1-0 lead with two outs in the first. McCutchen doubled down the left-field line to put himself in scoring position.
"He's done pretty well against us," McCutchen said of Samardzija.
"It was good we were able to get the run in the first inning and go from there."
The Cubs missed their only chance to get Liriano in the third.
Cody Ransom led off the third with a single, and Liriano walked Darwin Barney to put runners on first and second with no outs.
Samardzija then put down a bunt that hugged the grass along the third-base line. Liriano pulled Neil Walker off the bag at first as he tried to throw out the former Notre Dame wide receiver, allowing the Cubs to load the bases with no outs.
But Liriano escaped the jam.
Julio Borbon hit into a fielder's choice for the first out. Starlin Castro struck out for the second, and Anthony Rizzo flied out to right as the Pirates maintained a one-run lead.
The Pirates missed a couple opportunities to add to their advantage against Samardzija.
McCutchen led off the fourth with a double, his second of the game. But he did not advance as Jones and Neil Walker struck out and Russell Martin popped out to second base.
The Pirates again failed to drive in McCutchen when he was in scoring position and less than two outs.
This time, he struck out with one out but reached first on a wild pitch. He moved to second when Jones walked, bringing Walker to the plate. But Walker hit into a short-to-second-to-first double play to end the inning.
With Jason Grilli unavailable after throwing 34 pitches Tuesday night, Tony Watson and Mark Melancon kept the Cubs scoreless in the eighth and ninth innings.
Watson got Rizzo to strike out to end the eighth with the potential tying run on second.
Melancon also had the potential tying run in scoring position in the ninth, but he got Ryan Sweeney and Darwin Barney to hit bloop outs to second base to earn his first save since Aug. 26, 2012, when he was pitching for the Boston Red Sox.