Houston, TX (Sports Network) - Lance Berkman went 2-for-4 with an RBI double and the go-ahead two-run homer in the eighth as the streaking Houston Astros came back to nip the San Francisco Giants, 7-4, to sweep a four-game set.

Berkman's homer in the eighth was the big blow as the Astros swept their second straight four-game series for the first time in franchise history, and as they swept the Giants for the first time since 1970.

LaTroy Hawkins (2-1) picked up the win for getting one out in the eighth. Astros starter Brian Moehler surrendered four runs on eight hits in 5 1/3 innings for a no-decision.

Darin Erstad went 2-for-3 with an RBI for red-hot Houston, which has won eight straight and 16 of 20.

Keiichi Yabu (3-5) took the loss after allowing a run in one-third of an inning, while starter Kevin Correia gave up four runs -- three earned -- on seven hits in 6 2/3 innings, with five strikeouts and a walk.

Fred Lewis, who entered for center fielder Aaron Rowand after Rowand left with lower back tightness, homered for San Francisco, which had won three of four before this sweep.

Trailing 4-3, the Astros rallied with one run to tie the game in the seventh, and pushed ahead in the eighth. David Newhan singled to lead off the seventh, moved to second on a passed ball, and headed to third on a Humberto Quintero groundout. Erstad singled to center with two outs, plating Newhan to tie the game at 4-4.

Then Berkman struck to give the Astros the lead in the eighth. Miguel Tejada singled to right to lead off the eighth, bringing Alex Hinshaw in for Yabu. Berkman belted an offering from Hinshaw into the seats in left, his 25th of the season, and Houston took a 6-4 edge.

Quintero's RBI single later in the frame added an insurance run, and Jose Valverde tossed a perfect ninth for his 30th save of the season.

The Giants took the early lead, on an RBI single by Randy Winn and a Pablo Sandoval sacrifice fly, on his first major league at-bat, in the first inning for a 2-0 advantage.

Correia gave a run back in the second when, on a swinging strike three by Quintero, the wild pitch skipped away from Sandoval, allowing Hunter Pence to score from third. Pence had doubled to center with one out.

Winn's RBI double in the third boosted San Francisco back to a 3-1 edge. The Astros rallied, though, with two in the third to tie the game. Berkman knocked in one run with a double to left, and Geoff Blum followed with a sac fly to knot the game at 3-3.

Lewis pushed the Giants back in front with his leadoff homer, his ninth long ball of the season, to right-center in the sixth.