Another late failure for the Brewers
McDonald, who threw out Ryan Braun trying to score the winning run in the ninth Tuesday night, hit a liner that Braun in left field misjudged.
Wladimir Balentien hit a ground-rule double past diving right fielder Jody Gerut off Mike Burns (3-5), the fifth Brewer reliever, with one out in the 10th. Craig Tatum then hit into a fielder’s choice, advancing to second when Balentien was caught in a rundown.
Tatum scored on McDonald’s drive that went over the head of Braun, who broke in at first then watched the ball sail over his head.
Francisco Cordero pitched the 10th for his 27th save, one night after blowing his second save of the season.
Daniel Herrera (3-4) pitched an inning for the win.
Claudio Vargas failed to protect a 3-2 lead for Milwaukee starter Braden Looper, letting Cincinnati tie the game on his throwing error in the eighth.
Scott Rolen legged out an infield single, advanced on a groundout, stole third and scored when Vargas fielded pinch-hitter Kevin Barker’s chopper toward third and threw over the head of a leaping Prince Fielder at first.
With runners on first and third, Vargas struck out Drew Stubbs and then caught Paul Janish looking to end the threat.
Reds emergency starter Kip Wells, whose longest outing this season in three appearances was four innings of relief against Washington on Aug. 15, made a 2-0 lead stand up until the Brewers broke through with three runs in the fifth.
Gerut homered to make it 2-1, and an out later Wells walked Braun. After a visit to the mound from manager Dusty Baker, Wells, making the spot start for Aaron Harang, who had an emergency appendectomy over the weekend and is out for the year, gave up a homer to Fielder. The 435-foot towering drive to right barely stayed fair.
Fielder’s 34th home run of the season pushed his major league-leading RBI total to 112.
Wells walked three and struck out two in his first start since July 21, 2008, for Colorado. His start snapped a string of 66 consecutive relief appearances.
After hitting two solo home runs Tuesday in the Reds’ 8-6 extra-innings victory, Laynce Nix hit his 13th of the season, off Looper for a 1-0 lead. Looper leads the majors in home runs allowed with 32.
Corky Miller, promoted Tuesday from Triple-A Louisville in time to catch all 13 innings of Tuesday’s win, singled and scored on Janish’ single.