MILWAUKEE – Alex Rodriguez became the youngest member of the 400-homer club and a change in their routine got the Yankees back on the winning track with a 12-3 rout of the Milwaukee Brewers last night.

Joe Torre went to drastic measures to snap his slumping team out of its latest funk, canceling batting practice, juggling his lineup – sitting Hideki Matsui for the first eight innings, and even getting ejected for arguing. It worked.

A team that had hit .195 overall and .140 with runners in scoring position while losing seven of their first eight games on a season-long 12-game road trip, collected 16 hits and scored its most runs in two weeks.

Mike Mussina (6-4) was the beneficiary of the offensive breakthrough led by Rodriguez, who homered twice, went 4-for-4 and drove in four runs – his first RBI of the trip.

Rodriguez’s two-run shot off Chris Capuano in the first inning was his 399th, and his solo shot off Jorge De La Rosa in the eighth made the 29-year-old third baseman the 40th player in major league history to reach 400 homers.

Ken Griffey, Jr., who had been the youngest to reach the milestone, was 30 years and 141 days old when he hit his 400th homer.

Mussina gave up three runs and six hits in six innings, including Carlos Lee’s 15th homer. He walked one and struck out eight.

Derek Jeter and rookie Robinson Cano also homered for the Yankees, who had lost nine of 10.

The Yankees tagged Capuano (5-5) for seven runs, five earned, eight hits and three walks in four-plus innings.

The only damper for Torre was he wasn’t around to relish it in its entirety because he was ejected along with first baseman Tino Martinez for arguing with first base umpire Larry Vanover in the fifth inning.

New York broke it open with a three run fifth off Capuano, but not before Milwaukee third baseman Wes Helms, who lost his starting job last summer with shoddy defense, played a key role in two two-run innings for the Yankees.

After booting a Gary Sheffiled liner in the first, Helms charged a grounder from Rodriguez but bobbled it near the mound. It was ruled an infield single and Sierra followed with a double.

Martinez, starting at first base because Jason Giambi was a late scratch with back spasms, hit a ground-rule double to give the Yankees a 4-2 lead.

Jeter’s sixth homer, a solo shot, came off Julio Santana in the sixth. Cano’s homer was a two-run shot off Wes Obermueller in the seventh, his fourth of the season and the first pinch-hit homer of his career.

Matsui had a pinch-hit single in the ninth. Matsui hadn’t missed a start since September 26, 2003, when he wasn’t in the starting lineup for either game of a doubleheader against Baltimore. He appeared in both of those games and has played in all 384 games since joining the Yankees in 2003. Including his career in Japan, he has played in 1,634 consecutive games. That would be third on the all-time list behind Cal Ripken Jr. and Lou Gehrig.