Guzman went 3-for-5, scored twice and had three RBIs. He is batting .538 (21-for-39) during a streak that has made him first Washington-based player to get at least two hits in eight straight games in one season since Joe Cronin of the old Senators in 1933.
The Nationals are unbeaten when Guzman is in the lineup during his remarkable run. They won seven straight before manager Manny Acta gave him a day of rest Tuesday, when the Nationals were beaten 4-0 by the Phillies.
"If he needs a night off every now and then to hit triples and doubles, to drive in three, we'll give it to him," third baseman Ryan Zimmerman said. "He's been outstanding. It's nice to see him the whole year pretty much healthy. The first couple of years we didn't see the real Guz, and now you can see the kind of player he actually is."
Ryan Howard hit his 38th and 39th home runs for the Phillies, but reliever Chad Durbin (5-4) had a bad night as Philadelphia failed to keep pace with the Mets ahead of their crucial three-game series at Shea Stadium starting Friday. New York beat Milwaukee 9-2 on Wednesday afternoon.
"I think Friday is the most important game for us because we don't want to get ahead of ourselves," Phillies manager Charlie Manuel said. "We've got to win some games. I think if we keep falling back we're going to get in trouble."
The Phillies led 5-4 when Durbin entered the game with two outs and nobody on in the seventh. Manuel wanted a righty-righty matchup against Zimmerman, but the move backfired when Zimmerman deposited Durbin's third pitch to straightaway center field for his 11th homer.
"We've been asking a lot out of him," Manuel said. "But at the same time he's been so good, he's the guy we kind of have to go to and ride him. And why shouldn't we? He's been so good this year."
Durbin allowed three hits in four batters in the eighth, capped by pinch-hitter Ronnie Belliard's RBI single that gave the Nationals a 6-5 lead. J.C. Romero entered and walked Emilio Bonifacio, loading the bases for Guzman's three-run double that hit the base of the wall in left and made it 9-5.
"I was just trying to put the ball in play," Guzman said. "I saw the ball go into the gap, so 'Thank you."'
The Phillies rallied for two runs in the ninth off reliever Joel Hanrahan, but it wasn't enough as they lost their first series in Washington since 2006.
Saul Rivera (5-5), one of seven Nationals pitchers, threw a scoreless eighth to get the victory to finish an 8-1 homestand.
"We're playing well. We're confident," Zimmerman said. "We're doing all the little things right. And we're having fun. That's almost the most important thing. The new guys are filling in nice, and it's just a lot of fun when you're playing like this. You can't explain it. There's nothing that we did different, it's just you're rolling and you want to keep the momentum."
Notes: The Phillies are moving up Cole Hamels' next start so that he can face the Mets on Sunday in the series finale. Hamels, who pitched into the eighth inning in Tuesday's 4-0 win over Washington, has generally pitched on five days' rest instead of four. The switch means Kyle Kendrick will miss a start and could pitch out of the bullpen this weekend. ... Nationals RHP Collin Balester has a mild left gluteal strain, forcing the Nationals to juggle their rotation. He will not start as scheduled on Friday against Atlanta and instead will take his next turn Tuesday against the Mets. Shairon Martis will make his major debut Thursday against the Braves, and Jason Bergmann moves from Thursday to Friday. ... Phillies 2B Chase Utley, who barreled into Nationals C Jesus Flores in a failed attempt to steal home on Tuesday, was hit in the side with the first pitch he saw - a fastball from Odalis Perez. He was also upended by Lastings Milledge's hard slide that broke up a double play in the fifth. Flores is sidelined with a sprained ankle. ... Bryan Little had an eight-game multihit streak for the Montreal Expos (the former Nationals) over two seasons, spanning the last four games in 1983 and the first four in 1984.