PITTSBURGH (AP) _ Ken Griffey Jr. hit a three-run homer in the seventh inning after the Cincinnati Reds constantly squandered scoring chances before rallying to beat Pittsburgh 6-2 on Sunday.

The Reds stranded seven runners in the first six innings, leaving two on in the fifth and the bases loaded in the sixth, before Griffey hit a 1-0 pitch into the right-field seats with two on and two outs.

Griffey still isn't hitting for average in the NL _ he has a .213 average _ but his power is coming around. Seven of his 20 hits are homers and, despite his low batting average, he ended April with 24 RBIs.

Pinch-hitter Hal Morris singled and Sean Casey walked, one of five walks by Pirates starter Todd Ritchie in 6 2-3 innings, ahead of Griffey's first career homer against Pittsburgh.

Pirates manager Gene Lamont, who usually goes to the mound only to lift pitchers, talked to Ritchie before Griffey's homer and kept him in the game. Until then, Ritchie had handled Griffey, striking him out twice and getting him on a soft fly to left field.

An inning later, Lamont made a pitching change _ Brad Clontz for Scott Sauerbeck _ and Juan Castro followed a pitch later with a two-run homer, his first homer since June 17, 1998. Sauerbeck had walked Aaron Boone ahead of Castro's homer, one of nine walks by the four Pirates pitchers.

Griffey's homer was his third in six games and made a winner of rookie Rob Bell (2-1), who limited the Pirates to two runs and four hits despite walking five in six innings. He struck out seven.

The Pirates, losing their seventh in 10 games, threatened to retake the lead in the seventh by putting runners on first and third with two outs.

Even as two right-handers warmed up in the bullpen, Reds manager Jack McKeon allowed left-hander Dennis Reyes to pitch to the right-handed Kevin Young, and Young flew out to short right field. Young was 0-for-4 with two strikeouts.

Boone had an RBI groundout in the Reds' ninth.

The Pirates opened a 2-0 lead in the fourth on a pair of walks and Pat Meares' two-run double, their first hit in 19 at-bats with runners in scoring position in the series. They couldn't get another, stranding six runners over the final five innings.

Scott Williamson pitched the final two innings for his first save.

Notes: Reds LF Dmitri Young was 2-for-3 with two walks and is batting .500 (11-for-22) in the last six games. ... The Reds, 12-12 in April, haven't had a winning April since 1994. They started 9-14 last season before finishing 87-53. ... The Reds are 9-0 when they lead after eight innings. ... The Pirates have a league-low three saves. ... They went 9-15 in April and, like the Reds, haven't had a winning April since 1994. ... Meares has driven in five of the Pirates' nine runs in the four-game series, which wraps up Monday.