SAN DIEGO (AP) – Adam Dunn and the Cincinnati Reds knocked the San Diego Padres deeper into despair and out of first place in the sad-sack NL West.

Dunn’s grand slam in the fifth inning was Cincinnati’s third homer of the game, and the Reds beat San Diego 7-1 on Sunday to drop the Padres percentage points behind the Arizona Diamondbacks.

Wily Mo Pena and Rich Aurilia also homered to complete the three-game sweep for the Reds, who have won a season-high five straight.

The Diamondbacks (52-55, .4859) won 13-6 at the Chicago Cubs to leapfrog the Padres (51-54, .4857) atop baseball’s worst division. The Padres had led the West since May 26, when they were 28-19 and one-half game ahead of Arizona.

The Padres went 22-6 in May to set a franchise record for wins in a month and climb to 14 games over .500. Their luck changed along with the calendar, although the division is so weak that it’s taken this long for a change at the top.

The Padres have lost 12 of 13 overall and 35 of 53 since June 1. Clutch hits and home runs have practically disappeared, and their bullpen is running on fumes.

The Reds embarrassed the Padres in the series, outscoring San Diego 24-5 and making spacious Petco Park play like a bandbox. The Reds outhomered the Padres 8-0 and outhit them 33-18. The Reds had 21 extra-base hits while the Padres had just four.

Dunn went 6-for-14 with three homers, two doubles and nine RBIs.

San Diego has gone eight games without a homer. The Padres failed to connect off Eric Milton, who leads the majors with 31 homers allowed.

Milton (5-11) threw seven scoreless innings, allowing four hits while striking out six and walking none. He retired 16 of his final 17 batters and lowered his ERA from 7.03 to 6.65.

Woody Williams (5-8) did nothing to stop San Diego’s collapse. He lasted only five innings, allowing seven runs and seven hits, including all three homers. He struck out seven, but two of his three walks came ahead of Dunn’s slam, which was the first since Petco opened last season.

Williams walked Milton leading off the fifth, allowed Felipe Lopez’s single with one out and then walked Sean Casey before Dunn drove a 2-2 pitch deep into the seats in right field, his 31st. It was his second slam of the year and fifth of his career.

Pena homered to straightaway center with one out in the second, his 13th. San Diego’s Damian Jackson leaped vainly for the ball and almost tumbled over the fence.

Aurilia hit a two-run homer into the balcony on the fourth floor of the Western Metal Supply Co. brick warehouse just beyond the left-field corner with one out in the fourth. It was his 11th, and Casey was aboard on a leadoff double.

San Diego scored an unearned run on Mark Loretta’s groundout in the eighth.

Notes: Dunn’s other grand slam this year was July 9 at Arizona. … The Reds are undefeated in their last seven series, with four wins and three splits. … The Reds were 17-11 in July, their first winning month since May 2004 (18-11). … It was just the third time this season Milton pitched seven or more innings. … Padres backup INF Geoff Blum was traded to the Chicago White Sox for minor league pitcher Ryan Meaux. The Padres needed to make the move to open a roster spot for C Miguel Olivo, obtained Saturday night from Seattle.

AP-ES-07-31-05 1849EDT

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