CHICAGO -- At 18 games above .500, the Washington Nationals have already made a statement: they're going to be a major factor all season in the NL East.
"I think people are going to have to start believing. We have good pitching and good players," Guillen added.
Nationals starter Tony Armas, who missed the first five weeks this season with a groin pull, got his first road win as a starter in more than two years, lasting five innings plus and giving up two runs and seven hits.
"I'm just making progress. I'm happy. Every time out there I learn something new," Armas said.
"I just got to the fifth inning and then the relievers did the rest of the job. But I want to start pitching like I can pitch."
Armas (4-4) hadn't won a road start since April 10, 2003 -- at Wrigley Field -- and had been 0-6 in 10 starts since.
"Tony is still trying to get it all together. He was better today and his pitch count wasn't too high," Washington manager Frank Robinson said.
"He kept us in the game."
Chad Cordero pitched a perfect ninth for his major league-leading 29th save. He's converted 26 straight opportunities.
Chicago's Derrek Lee continued his remarkable first half with three more hits, including his 25th homer, a triple and a single.
Needing a double to hit for the cycle, Lee flied to center in the eighth inning.
"I was thinking just get on base and hopefully Jeromy (Burnitz) or Aramis (Ramirez) or somebody would hit a home run and tie it up," said Lee, who raised his average to .386 and is expected to make his first All-Star team Sunday.
"I feel like I'm going to have a good at-bat and put a good swing on the baseball and whatever happens, happens," Lee said.
Armas said Lee has such a good feel at the plate, it's difficult to get him out.
"I threw away, inside, he's just a guy you can't pitch to right now," Armas said. "You make high pitches, low pitches, he just hits everything."
But despite Lee's three-month tear, the Cubs are still scuffling offensively, prompting manager Dusty Baker to promise some changes, especially at the top of the order where heavily booed Corey Patterson is in a 2-for-20 slump after an 0-for-4 Saturday.
"We've all been there, you got to keep fighting and work your way out of it," Lee said about Patterson.
"Fans have a right to do what they are going to do. They're frustrated, so that's what they do. They boo."
Guillen hit his 17th homer in the first off Jerome Williams (1-3), a high fly ball that just carried over the left field fence with the wind blowing in at 10 mph.
Guillen also started a two-run fourth with a leadoff single, moved to second as Vinny Castilla walked, to third on a sacrifice and scored on Wil Cordero's sacrifice fly. Gary Bennett then delivered a two-out RBI single to put Washington up 3-0.
Lee's triple and an RBI grounder by Ramirez got the Cubs a run in the fourth.
But the Nationals responded in the top of the fifth when Brad Wilkerson hit a drive to the left center field wall that Todd Hollandsworth nearly caught before losing possession as he came down through the ivy. It went for a triple, and Junior Spivey followed with a sacrifice fly.
"I lost my balance when I jumped. I thought I was going to hit the wall and I didn't and then it was just chaos," Hollandsworth said. "I felt the ball among the leaves."
Lee homered to start the sixth and cut the lead to 4-2. After Armas walked Burnitz, he was replaced by Gary Majewski. Ramirez then hit a liner toward right that first baseman Cordero snagged, easily catching Burnitz off the bag for a double play.
Williams lasted seven innings, giving up five hits and four runs.
- The announced crowd of 40,488 on a 67-degree day was the largest of the season at Wrigley Field.
- Armas' 2003 season was cut short by shoulder surgery. He did not pitch after April 20 that season.
- Nationals 1B Nick Johnson missed his fifth straight game with a bruised right heel. SS Cristian Guzman was also out of the lineup with a sore left hamstring, an injury sustained Thursday.
- Ramirez returned to the Cubs' starting lineup. He'd been forced out of Thursday's game after being hit on the left shin with a pitch and had pinch-hit on Friday.
- The Cubs have dropped three straight.