McDonald led off the bottom of the ninth with a soft single through the left side against Pirates reliever Jesse Chavez. Craig Tatum then slashed a single through the right side. Paul Janish's flyout to deep right field allowed McDonald to take third base and set up the winning run.
While facing Drew Stubbs, Chavez (0-4) bounced a 2-0 pitch in the dirt, and the ball rolled through catcher Jason Jaramillo's legs to the grass behind home plate. McDonald broke for home and scored with a headfirst slide.
"I saw it bounce away a little bit," McDonald said. "The ninth inning at home, you have to be aggressive in that situation. It didn't get away that far. But it's a tough play for the catcher and pitcher to get you out there. I was going to take my chances."
Nick Masset (5-1) pitched one scoreless inning with one hit allowed for the victory before an announced crowd of 13,051 at Great American Ball Park. However, about 1,800 actually took in the game that was a makeup for an April 10 rainout.
The ballpark's scoreboard crew showed it had a sense of humor about the situation. One fan surrounded by empty seats was shown on the video board as "All By Myself" by Eric Carmen blared on the speakers.
"I could hear everybody today," Baker said of the fans.
Two pitches into Pirates starter Daniel McCutchen's Major League debut, Stubbs hit a leadoff homer into the left-field seats. It was Stubbs' second long ball of his career and the first leadoff homer for the Reds this season.
Cincinnati starter Kip Wells struggled to get the ball over the plate, yet he gave up only two runs over six innings. Both of them came in the top of the second. After a two-out walk and a hit batter, Wells gave up Jaramillo's RBI single to left field and McCutchen's RBI single to right.
Wells also allowed four walks in the game, but he got it together in time to retire his final eight batters before exiting after 107 pitches.
"It helped out a lot," Baker said of Wells' effort, "because I really didn't want to go to the bullpen that early. We were hoping to get six or seven innings out of him. He ran that pitch count up early. He didn't have command of the strike zone and threw a couple of big-time double plays."
"At that point, I was on life support," Wells said. "I really didn't feel like I started with a whole lot of strength. My stuff was still OK. I was still laboring, regardless. At this point, there are no excuses for not getting the job done. You can't do anything but challenge hitters."
In the third inning, a one-out RBI single to center field by Drew Sutton and Scott Rolen's two-out RBI single to right gave the Reds a 3-1 lead. However, reliever Carlos Fisher couldn't hold it in the seventh, allowing a Ronny Cedeno leadoff triple and a Jaramillo RBI single that tied the game.
Until Chavez's mistake in the ninth, the game had all the makings of another extra-innings affair for Cincinnati. The Reds were relieved it didn't end up that way, as they took about a three-hour break before Game 2.
"The only thing about this is you can't have a victory beer after the game," Baker said.