PITTSBURGH -- For the second straight game, the Pittsburgh Pirates made the most of one productive inning.
Walker's 18th home run put the Pirates ahead 3-0 against Alfredo Simon four batters into the game. Pittsburgh's winning streak matches its longest of the season.
In the thick of the NL playoff race, the Pirates have won the first two games of the three-game series despite scoring in only two innings. They had a two-run rally in the eighth Friday for a 2-1 victory.
"It's a testament to our pitching," Walker said. "We only scored three runs today and Vance and the bullpen made it stand up. That's what won it for us."
Worley (6-4) allowed two runs -- one earned -- and three hits in 6 1/3 innings to snap a career-worst, three-start skid. Mark Melancon pitched a perfect ninth for his 26th save after Justin Wilson and Tony Watson combined for 1 2/3 scoreless innings.
"It's just a lot of fun to be pitching in this situation," Worley said. "Every game is important. You have to be excited about that."
Despite retiring 12 batters in a row between the third and sixth, Simon (13-9) fell to 1-6 since pitching in his first All-Star game last month.
Todd Frazier homered for the Reds, who lost their seventh road game in a row. Simon allowed four hits and three walks in seven innings while striking out seven.
"This was pretty much the story of his second half," Cincinnati manager Bryan Price said. "He has some trouble getting out of the gate and then he's fine. The bottom line, though, is we have to score more than two runs. It's tough to win when you don't score runs consistently, and it's been a problem all season."
The game featured only seven hits, four by Pittsburgh.
The Pirates are a major league-best 24-9 at home since June 19.
Reds: No injury updates.
Pirates: 3B Pedro Alvarez (sprained left foot) missed his third straight game, and RF Travis Snider (strained right hamstring) sat out for the second day in a row. ... RHP Charlie Morton (right hip inflammation/sports hernia) won't be able to get stretched out enough to rejoin the starting rotation by the time he is eligible to be activated from the disabled next Friday, but said he would be willing to pitch in relief.
Reds: RHP Johnny Cueto (15-8, 2.26 ERA) will look to snap his two-start losing streak in which he has allowed six runs over 11 1/3 innings for a 4.76 ERA. He faces LHP Francisco Liriano in a rematch of last year's NL wild-card game. Cueto is 16-4 with a 2.26 ERA in 25 career starts against Pittsburgh.
Pirates: Liriano (3-10, 3.98) is 0-3 with a 4.03 ERA in his last five starts, but he pitched six scoreless innings Monday against St. Louis. Though he won the wild-card game last season, Liriano is 0-5 with a 4.25 ERA against the Reds in seven regular-season starts.
MORE BENCH HELP
The Pirates recalled a player from Triple-A Indianapolis for the second straight day, bringing up INF Brent Morel to help off the bench with Alvarez and Snider unavailable. 1B-OF John Lambo was recalled on Friday night.
LHP Jeff Locke was optioned to Indianapolis in a procedural move. He will remain with the Pirates and be recalled Monday when major league rosters expand. Locke is scheduled to start Tuesday night at St. Louis.
BAD YEAR FOR BRUCE
Reds RF Jay Bruce called this season "the most embarrassing year of my life." He went 0 for 3 with two strikeouts, dropping his batting average to .217.
Bruce is 4 for 32 with 15 strikeouts in his last nine games. He is 2 for 12 in his career against Worley.