PITTSBURGH -- Four innings earlier, all finally seemed so right again for the Pirates.
One swing of James McDonald's bat produced the spark that the club had been desperately awaiting for days. It expunged an early deficit and aroused a crowd of 29,317.
But all momentum that had been built during a six-run fourth inning was lost when the Pirates' bullpen let a two-run lead slip away in the eighth. With three runs, all charged to Daniel McCutchen, the Cubs went on to celebrate a 7-6 victory at PNC Park on Thursday night.
That extended the Pirates' losing streak to a season-long seven games, sent Chicago back home with its first four-game sweep in Pittsburgh since 1959 and left manager Clint Hurdle again answering questions about the use of his bullpen.
"Our team fought back," McCutchen said. "It's just bad. Bad that our bullpen, starting with me, couldn't hold the lead."
Bouncing back after allowing three early home runs, McDonald ended his first seven-inning start since last September with three scoreless frames. He left with a 6-4 lead.
Rather than going to Chris Resop, who Hurdle wanted to avoid using altogether, or Jose Veras, who had pitched in two straight games, Hurdle believed his best option would be a well-rested McCutchen. And Hurdle was ready to bring closer Joel Hanrahan in for a four-out save, if his 'pen could get him there.
There would never be such an option.
Two quick singles got McCutchen into immediate trouble. A 2-2 fastball then grazed Darwin Barney to load the bases.
"I kind of got a little amped up, I guess, and tried things I normally don't try," McCutchen said. "I was just overthrowing a little bit."
Jason Grilli entered next and promptly allowed an RBI single. Then came Joe Beimel, who pushed across the tying run by walking Carlos Pena with the count full.
"It's one of those situations where on 3-2, I didn't want to give into him right there and give him a fastball down the middle with no outs," Beimel said. "In that situation, with the tying run on third and no outs, it's a little hard to be patient as a hitter. I was trying to kind of feed off his aggressiveness."
Beimel turned the mess over to Veras, who recorded three straight outs. But the go-ahead run scored on the first, a sacrifice fly off the bat of Marlon Byrd.
The three unanswered runs cost McDonald a win and the Pirates a chance to inch a half-game closer to the Brewers in the division standings. Instead, Pittsburgh slipped to seven games back and two games beneath the .500 mark.
"Through the course of a season, things like this are going to happen," Beimel said. "It's how you rebound after a streak like this. We've just still got to believe that and hopefully pull that together."
What stung so much was that the late-inning crumble zapped all the energy that had been built back up during a six-run fourth inning.
The Pirates had fallen behind, 4-0, early when Geovany Soto, Pena and Blake DeWitt homered off McDonald. The trio of blasts brought the Cubs' total for the series to 10.
Yet the Pirates found a way to strike right back.
A leadoff fourth-inning double by Garrett Jones put the first baseman in position to score on an RBI single by Ryan Ludwick. The hit was Ludwick's first as a Pirate, as he began his tenure with the club 0-for-8.
Singles by Pedro Alvarez and Ryan Doumit followed, and a second run scored on Xavier Paul's fielder's choice. Then, after a two-out walk to Brandon Wood, McDonald laced a ball into the gap in left-center to plate three runs.
The double was just the second extra-base hit of McDonald's career. The RBIs were his first.
"[The] hitting coach told me to think about hitting the ball up the middle to left-center," said McDonald, who was 3-for-38 before Thursday. "I was really focused. I let balls down in the zone go until I got a pitch I liked, then I swung. It feels good to get a big hit in that situation."
Andrew McCutchen capped the inning with an RBI double to score McDonald.
The inning output was the largest since the club scored six times in the sixth inning against Detroit on May 20. The team had plated only nine runs in the first three games combined.
"I had a game plan, had a good game going on," said Cubs starter Rodrigo Lopez, who didn't return after the fourth. "And all of a sudden, with that at-bat where the pitcher came up, that changed my whole game."
With a lead in hand, McDonald didn't allow a hit in his final three innings on the mound. His ability to get through the seventh -- and with a modest pitch count of 99 -- was a notable step forward. He had gone 24 straight starts without doing so.
"For me, it was an accomplishment," McDonald said. "I feel like it's been on my back all year, not going seven innings. It was good going seven, but it would've been better going six with a win for the team."
Blown saves have now cost McDonald (7-5) three wins this season. Beginning with the crushing 19-inning loss last week, five of Pittsburgh's last nine defeats have been by one run.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.