"I had pretty decent command; they just hit the ball when they needed to," McDonald said. "This is a loss I can live with. I competed, went out there and gave everything I had. I had good stuff. They got me today."
McDonald (10-4) took the loss on a night when Pittsburgh acquired left-handed starter Wandy Rodriguez and cash from Houston in exchange for three prospects
-- outfielder Robbie Grossman and lefties Rudy Owens and Colton Cain.
"We like the innings, we like the strikeouts, we like the ERA, we like the competitor," general manager Neal Huntington said, regarding Rodriguez. "He has very quietly been one of the better pitchers in Major League Baseball over the last three, four years."
Rodriguez last pitched on Monday, allowing three runs in seven innings against Cincinnati, which is ahead of Pittsburgh for the National League Central lead by 2 1/2 games.
McDonald threw 87 pitches across six innings, allowing five runs while striking out six and walking three. One of his walks was intentional, and all of them came in the fifth inning.
That's when McDonald first ran into serious trouble. His third walk, issued to opposing starter Paul Maholm, loaded the bases. David DeJesus then stepped in and made McDonald pay for the free passes, driving in two runs with a double into the right-field corner.
"I got in the way on the intentional walk," said Pirates skipper Clint Hurdle, who liked what he saw from McDonald. "Sometimes, they make those same pitches and they don't get hit. Tonight, they were hit. The mistakes were made. They hit. They took advantage of them."
An inning after the double, Alfonso Soriano continued his punishment of the Pirates. He blasted a two-run shot into the left-field seats, this coming a night after he drove in both of the Cubs' runs in a 2-0 series-opening win.
"Soriano hit a good pitch," McDonald said. "Castro, it was a bad pitch, but he still hit it. It's not easy just to hit homers. I tip my hat. They hit the ball when they needed to."
The Pirates, for their part, were not to be shut out on back-to-back nights. In the fourth inning, Garrett Jones turned on a high fastball from Maholm (9-6) and sent it into the right-field seats for his 14th homer of the season.
"I missed the pitch to Jones," Maholm said, "and he's been doing what he's been doing all year."
The long ball tied the game -- temporarily -- and gave the Pirates their first run since the seventh inning of Sunday's 3-0 win over the Marlins. It was Jones' first big fly off a left-handed pitcher since last August, when he hit a walk-off homer off Arthur Rhodes of the Cardinals.
In their last two games, the Pirates have scored one run and managed seven hits.
"This isn't going to be easy," Hurdle said. "Every night you go out there, you've got to earn your way on the field of play."
Against his former club, Maholm was masterful. In winning his fifth straight decision, the Cubs lefty added to his trade value by holding the Pirates to four hits over eight innings. He racked up seven strikeouts and issued one walk.
McDonald, on the other hand, is trending downward, at least statistically. In his last three starts, the righty has allowed five home runs and posted an 8.62 ERA. On Tuesday, his ERA this season rose to 3.15.
"He was so much better across the board than his first two starts [of the second half]," Hurdle said. "Downhill plane to his fastball, consistent velocity, his breaking ball was better, his slider was better."
McDonald, too, seemed encouraged by Tuesday's performance.
"I think I took a step forward from my previous two [outings]," McDonald said. "I went after guys. I had good stuff. I think it was decent, even though the results weren't there today."
The Pirates' second defeat in as many nights ensured that they would lose their first series at home since the Mets took two of three games here from May 21-23.
"We've got more work to do," Hurdle said. "We've got to find a way to try and scratch out some more hits, some more runs when things are tough and we're facing guys that are pitching effectively."