WASHINGTON -- Giants manager Felipe Alou's pregame thoughts on starter Brad Hennessey proved rather prophetic Wednesday night. The righty had lost five straight games dating back to late July, but Alou said Hennessey would be fine if he could get through the first few innings.

The starter struggled in the first two frames, but breezed afterward. He threw a career-high 7 2/3 innings and took advantage of an early homer by Barry Bonds -- in addition to launching one of his own -- to help the Giants stretch their winning streak to five games with a 5-1 win over Washington before 32,076 at RFK Stadium.

Hennessey (5-8) gave up one run on three hits in the first two innings, but quickly settled down. After a one-out walk to Nick Johnson, he retired the next 15 Washington batters before Brad Wilkerson walked with two outs in the eighth to end Hennessey's night. Nevertheless, his effort was good enough to earn him his first victory since July 28 against Milwaukee. He had gone 0-5 in his previous nine starts.

"The kid threw a [heck] of a game," Alou said. "The first couple of innings [were important]. You have to get to him early. We know he's capable of [pitching well]. He's done that quite a bit."

Hennessey said that the Bonds homer helped him relax and get loose. Bonds blasted a 1-1 pitch from Washington starter John Patterson (9-6) off the wall behind the right-field bullpen to give San Francisco (71-80) a quick 2-0 edge in the top of the first. It was the fourth straight game in which he's homered. Bonds now has 707 dingers for his career.

"It was a good pitch," Patterson said of the gopher ball he served up to Bonds. "I put the cutter in on him. It was going to be a ball down and in. I don't know how he hit it. We were all talking about it after we came into the dugout."

Hennessey was certainly happy to go to the mound in the first with a two-run lead.

"[Bonds] has been amazing so far," Hennessey said. "It's nice to get that early lead and ... settle in a little bit, knowing you don't have to be perfect from the get-go."

Bonds was lifted for a pinch-runner after being intentionally walked in the seventh and wasn't available to address the media after the game. Alou said his slugger wouldn't start Thursday, but could be available to pinch-hit.

Lance Niekro gave the Giants a 3-1 lead with an RBI single in the fourth. Hennessey then doubled and scored on Randy Winn's RBI single in the fifth.

The righty then became the third pitcher in the Majors this year to hit at least two homers when he sent Patterson's first pitch into the left-field bullpen in the seventh for his second homer of 2005 to give San Francisco a 5-1 lead. Eric Milton of Cincinnati and Washington's Livan Hernandez are the other pitchers with multiple dingers.

Hennessey, who played shortstop in college, helped his own cause by going 2-for-3 with an RBI and two runs scored. His performance at the plate increased his average to .229 on the season.

His other homer this year came in his victory over the Brewers.

"I always try and take pride in my hitting because I used to play way back when," Hennessey said. "It always helps, and so far, when I do well at the plate it seems like I do well on the mound too."

Wednesday's game was much like Tuesday's win over Washington (77-75) in that the Giants got a little help from a lot of places. Hennessey contributed on the mound and at the bat, while Bonds helped with his homer, and Niekro and Moises Alou also pitched in.

The younger Alou helped the Giants manufacture their third run in fourth. He led off with a double to right-center, then made a daring dash for third on Ray Durham's fly out to right, barely beating Jose Guillen's throw. Niekro then drove him in with a single to center.

Alou has been battling leg problems all season, but said he's trying to contribute whenever possible.

"I am better, but I'm not that healthy," Alou said. "I have to pick my spots. For [Guillen] to get me, I [knew] it would have to be a really good throw."

The win left the Giants five games behind San Diego, which nabbed a 5-2 victory over Colorado. The Giants skipper repeated his recent mantra -- that his Giants simply have to keep winning to make the upcoming four-game series with the Padres meaningful and to put pressure on their division rivals.

"We know we still have a shot at making the playoffs," Alou said. "Every play, every pitch, every decision is big."