PITTSBURGH -- These last few days have proved what Pedro Alvarez has felt all along.

"I've always believed that hitting is contagious," Alvarez said, "and I think we're a perfect example of that in the last few days, and we just need to keep it going."

Alvarez became the first Pirates rookie to have back-to-back multi-homer games, leading his club to a 15-3 victory over the Brewers on Wednesday before 13,532 fans at PNC Park.

Before the All-Star break, the Pirates ranked last in the Majors in runs, hits and batting average. Through 88 games, they had scored nine or more runs just three times. Pittsburgh entered the midway point of the season on a six-game slide at Houston and Milwaukee.

Six games against the Astros and Brewers since the break -- in the comforts of PNC Park this time -- have changed a lot of things.

The Pirates have slowly but surely climbed up the statistical ladder in each of the aforementioned categories, crossing the plate nine or more times in four of their last five games. All four of those games have been wins, culminating with a season-high in runs scored Wednesday night.

The Pirates had not scored 15 in a game since Sept. 17, 2008. They recorded 18 hits, their third game with 17 or more hits in their last five games. They are hitting .372 as a team during this stretch.

Pittsburgh improved to 23-22 at home this season and 4-2 overall since the All-Star break.

Every starting Pirates position player recorded at least two hits, save for catcher Ryan Doumit. Erik Kratz entered in the fourth after Doumit felt light-headed and nauseated following a first-inning collision with Rickie Weeks at the plate, which scored the game's opening run.

The Bucs answered right back, however, scoring twice in the bottom half of the frame. They scored runs in six different innings on the night.

Alvarez led the way, lifting a first-pitch fastball to center in the fifth with Garrett Jones aboard. The right-field foul pole may have been the only thing keeping his second homer, a solo shot, in the ballpark after he smacked a 2-2 curve in the eighth.

Alvarez finished 3-for-5 with three runs and three RBIs. Four of the rookie's seven home runs have come in the last two days.

Delwyn Young drove in a career-high five RBIs, one night after Alvarez did the same. It marked the first time Pirates teammates had at least five RBIs in two straight games since Al Oliver and Rennie Stennett did so May 3-4, 1973.

Young's fourth home run of the year, a three-run shot that snuck inside the foul pole in left, highlighted a nine-batter, six-hit, six-run fourth that started with consecutive base hits from Jones, Alvarez and Lastings Milledge. Ronny Cedeno's surprise bunt attempt with two on and one out provided the twist, as a charging Prince Fielder couldn't get Alvarez, the second run of the inning, at home. Jose Tabata added an RBI single in the frame and finished the game 2-for-4 with three runs scored.

"I wish every night was a career night," Young said. "But anytime you get in there you want to keep up with the Walkers and the Joneses and everybody else who came up. So not that it's pressure, it's just trying to do the best that we can."

The Pirates even got to give their bullpen a bit of a break, thanks to Zach Duke's six-plus innings of work in which he allowed just three runs -- two earned -- on six hits. Duke earned his first win against the Brewers since Sept. 11, 2006, a span of eight starts. The left-hander also singled to lead off the sixth, marking the second straight night he reached base. Duke pinch-hit Tuesday and struck out but went to first on a wild pitch.

"It was big," Pirates manager John Russell said of Duke's start. "Our bullpen again was taxed a little bit. But to come out, we got the lead and really added on, and for him to go out and consistently get us back in the dugout was big for him. Our bullpen needed it."

One night after teammate Dave Bush surrendered 10 runs, Randy Wolf gave up career-highs of 12 runs and 13 hits but managed to last 5 2/3 innings because the Brewers have also suffered from a taxed bullpen.

Wolf watched video of the demolition for about 20 minutes after the game, drawing the obvious conclusion.

"I saw that I got my butt kicked," Wolf said. "There's really not too much to say about that. When you give up 12 runs, you're not executing your pitches."

Major League pitchers have allowed 10 or more runs this season 13 times, and four of them are from the Brewers, all in the last two weeks. Milwaukee starters have allowed 10 runs in three of the last four games. The last two have come against the Pirates, a team that was victim of a 20-0 defeat to this same Brewers club back on April 22.

With a far different look from three months ago, the Pirates were the ones enjoying a rout on Wednesday.

"Very fun, obviously," Alvarez said. "To go out there and play some good baseball, come out winning, it's what we want to do. And it makes it much better when you have a good day. Then at the end of the day you can share a victory with your teammates."