Alfredo Simon pitched 6 2/3 strong innings to become the National League's first 12-game winner and Brandon Phillips had two hits and an RBI as host Cincinnati closed within one win of a five-game sweep of Chicago.
Simon (12-3) struck out eight while limiting the Cubs to one run and four hits, recording his eighth straight quality start and doubling his career high for victories in a season. Billy Hamilton, Jay Bruce and Ramon Santiago also drove in runs for the Reds, who have won five straight.
Anthony Rizzo homered among two hits for the Cubs, who have lost six straight following a four-game winning streak. Dallas Beeler (0-2) lasted five innings and gave up four runs on six hits and four walks in his second major-league start.
Santiago put the Reds on the board with an RBI double in the second, but Rizzo answered with a solo blast in the third to tie it. Cincinnati broke it open in the fifth, as Hamilton tripled in a run and scored on Phillips' RBI single before Bruce's run-scoring single made it 4-1.
Simon retired 13 straight hitters following Rizzo's homer before issuing a walk to Welington Castillo to end his evening. Cincinnati's bullpen put together 2 1/3 scoreless innings - running its total to 11 1/3 over the past two days - with Aroldis Chapman striking out the side in order in the ninth for his 19th save.
GAME NOTEBOOK: Cubs manager Rick Renteria was ejected in the fifth inning after arguing a non-reviewable fair/foul call with third-base umpire Andy Fletcher. It's the fifth ejection of the season for Renteria. … Hamilton left the game with a tight left hamstring, while Phillips left with sprained left thumb; X-rays were negative on Phillips. … Rizzo is the first Cubs player with 20 homers before the All-Star break since Derrek Lee in 2005 and the first left-handed Chicago hitter to reach the mark before the break since Rick Monday in 1973.