CINCINNATI (AP) — How bad are things going for the Houston Astros this season? Roy Oswalt can’t even beat the Reds.

Joey Votto hit a two-run homer in the seventh — an inning after Oswalt failed to hold a lead against the team he’s beaten like no other — and Cincinnati rallied for a 6-4 victory Tuesday night that sent the Astros to their season-high sixth straight loss.

This one left them a little dazed.

‘‘With your ace on the mound, you figure if you don’t have it, you’ve got a pretty good chance of getting it,’’ manager Cecil Cooper said. ‘‘We let two leads slip away there. We just need him to step up and be who he’s supposed to be.’’

Oswalt has dominated Cincinnati since 2001, when he beat the Reds as a rookie for his first big league victory. He’s 23-1 in his career against the Reds, who have never scored more than four earned runs off him in a game. This season, he has lost his touch.

In three starts against the Reds, Oswalt has failed to get even one win. This one slipped off the middle and index fingers of his right hand.

Oswalt knocked down a comebacker in the fifth inning, the ball deflecting off those two fingers. When he came back to pitch the sixth with a 4-3 lead, he had trouble feeling the ball.

‘‘I came back out there and couldn’t really squeeze the ball well,’’ Oswalt said.

He got two outs with one runner aboard, then walked a batter and hit another to load the bases. Then, he walked pinch-hitter Jonny Gomes on four pitches to force in the tying run.

‘‘I couldn’t really throw it where I wanted to,’’ Oswalt said.

The way the Reds have fared against him historically, they knew they were going to need some help. They were surprised that Oswalt gave it to them.

‘‘He was good tonight, but he wasn’t as good as he usually is,’’ manager Dusty Baker said. ‘‘We got to him.’’

Votto’s homer off Tim Byrdak (0-1) snapped a 4-all tie and sent the Reds to their third straight win, which matches their season high.

Nick Masset (2-0), who was activated off the disabled list before the game, got the victory with one inning in relief. Francisco Cordero pitched the ninth for his 13th save in as many chances.

Votto was in the lineup after having no problems with his balance during pregame warmups. The first baseman has been bothered by an inner-ear infection for the last 10 days, causing dizzy spells that have repeatedly forced him to leave or skip games.

‘‘Today’s really the first game I’ve felt pretty good,’’ Votto said.

He struck out twice and grounded out in his three at-bats against Oswalt, then connected off Byrdak for his eighth homer — an opposite-field drive to left off a fastball that was low and away.

‘‘I just got a good swing on the ball,’’ said Votto, who has eight homers. ‘‘It was a pitch I normally wouldn’t swing at.’’

Notes: The start of the game was delayed 39 minutes by rain. … Astros SS Miguel Tejada extended his hitting streak to 10 games. … Houston INF Jason Smith has accepted his assignment to Triple-A. He was designated for assignment on Friday and cleared waivers. … Houston’s Edwin Maysonet started at 2B for Kaz Matsui, who has a sore hamstring and will get a couple of days off. … Struggling Reds leadoff hitter Willy Taveras was out of the lineup, getting some rest. He pinch hit and grounded out. … Masset had been on the DL with strained muscles in his side.

Reds 6, Astros 4

Houston Cincinnati

ab r h bi ab r h bi

Bourn cf 5 0 1 0 Dickrsn cf 4 1 1 0

Tejada ss 5 1 3 0 HrstnJr 2b 2 1 0 0

Brkmn 1b 3 1 1 0 Votto 1b 4 1 1 2

Ca.Lee lf 4 1 2 0 RHrndz c 4 0 1 2

Pence rf 3 0 0 0 Bruce rf 4 1 1 0

IRdrgz c 4 0 1 2 L.Nix lf 4 1 2 1

Kppngr 3b 3 1 1 1 AlGnzlz ss 3 0 1 0

Maysnt 2b 4 0 2 1 ARosls 3b 3 0 0 0

Oswalt p 2 0 0 0 Owings p 2 1 1 0

Byrdak p 0 0 0 0 Lincoln p 0 0 0 0

Erstad ph 1 0 0 0 Herrer p 0 0 0 0

Hwkns p 0 0 0 0 Gomes ph 0 0 0 1

Masset p 0 0 0 0

Weathrs p 0 0 0 0

Taveras ph 1 0 0 0

Corder p 0 0 0 0

Totals 34 4 11 4 Totals 31 6 8 6

Houston 000 301 000 — 4

Cincinnati 002 101 20x — 6

DP—Cincinnati 2. LOB—Houston 8, Cincinnati 6. 2B—Tejada (16), I.Rodriguez (7). 3B—Berkman (1). HR—Keppinger (2), Votto (8), L.Nix (4). S—Oswalt, Hairston Jr..

IP H R ER BB SO

Houston

Oswalt 6 7 4 4 2 5

Byrdak L,0-1 1 1 2 2 1 2

Hawkins 1 0 0 0 0 0

Cincinnati

Owings 5 6 3 3 4 3

Lincoln 1-3 2 1 1 0 0

Herrera 2-3 1 0 0 0 1

Masset W,2-0 1 1 0 0 0 1

Weathers H,7 1 0 0 0 0 0

Cordero S,13-13 1 1 0 0 0 0

HBP—by Oswalt (A.Rosales). PB—I.Rodriguez. Umpires—Home, Mike Everitt; First, Mike Estabrook; Second, Brian Gorman; Third, C.B. Bucknor. T—2:57 (Rain delay: 0:39). A—15,619 (42,319).