Dunn, who went more than 400 days between appearances, made his third start for the Reds this season and recorded his first win.
Dunn, the No. 1 draft pick of the New York Mets in 2016, pitched five innings and held the Pirates to one run and three hits. The one run was a fourth-inning home run by Rodolfo Castro when the Reds owned a five-run lead.
Four occupants of the Reds’ bullpen held the Pirates scoreless over the final four innings.
The pitching match-up was a duel between former No. 1 picks now pitching for different teams. The Pirates started Tyler Beede, a No. 1 pick in 2014 by the San Francisco Giants out of Vanderbilt University.
The Reds chased Beede after four with five runs and six hits that included a home run by Fraley that was headed for Erie, Pa. before landing in the Allegheny River.
Fraley, plopped into the leadoff spots the last few games, is hitting more like a clean-up hitter.
In the fourth inning, with the Reds in front, 3-0, Fraley crushed a down-range home run, a 437-foot drive that cleared the right field bleachers and splashed down in the Allegheny.
It was only the sixth ball in PNC history to reach the Allegheny on the fly. It was Fraley’s third home run in five games an gave the Reds a 5-0 lead.
Before Fraley’s home run, the Reds scored a run in the third without a hit. Fraley walked, took second on a ground ball and scored on an error.
The error was by Pittsburgh’s 6-foot-7 rookie shortstop O’Neil Cruz. Cruz owns a Howitzer for an arm but has little idea of accuracy. His misfire Saturday followed a throwing error Friday.
The Reds added two in the fourth on singles by Donovan Solano and T.J. Friedl and a two-run double by catcher Austin Romine, batting .196 at the time.
The Reds didn’t score again until the ninth when they put the game in the win column with five runs on a streak of seven straight singles.
Mike Moustakas rolled a one-out run-scoring single to right, Solano poked an RBI single to left and Nick Senzel’s run-producing single made it five straight singles.
Pinch-hitter Aristides Aquino kept the singles streak going with a run-scoring drive to left, Cincinnati’s sixth straight hit and a 9-1 lead.
After a brief pause for a pitching change, Jose Barrero blooped a broken bat single to center, another run and the seventh straight single and an 10-1 lead.
Ian Gibaut replaced Dunn in the sixth and the Pirates loaded the bases with two outs before Gibaut squeezed out of the dilemma.
Buck Farmer pitched an easy-chair 1-2-3 seventh inning and Hunter Strickland issued a harmless one-out walk in the eighth.
Art Warren, who hadn’t pitched since July 2 while on the injured list, pitched the ninth. He walked the first batter he faced, then retired the next two, issued another walk, then ended it by striking out Kevin Newman.
The victory, the Reds third in 11 games, enabled them to climb out of a last-place tie with the Pirates.
With the series even at 1-1, both teams send problem-plagued pitchers to the mound Sunday afternoon. It will be Cincinnati’s Mike Minor (1-and-10) against Pittsburgh’s Zach Thompson (3-and-9) in another game to decide the occupants of last place in the National League Central.