"Anytime you get runs, it allows you to settle down," Lowe said. "First pitch strikes was important to me tonight. That's a team that is very aggressive, so you can't just throw any first-pitch in there and get lazy. You have to make it a quality pitch. The defense made a lot of really good plays behind me and kept the momentum on our side."
Perez (3-8) lost for the fourth time in five decisions, allowing six runs and eight hits in four innings. The Nationals have been shut out in three of his last four starts.
Lowe (8-8) struck out four, walked one and retired his last 13 batters while sending the Nationals to their eighth straight loss at Dodger Stadium. He also had a pair of singles, one of which drove in a run.
The right-hander gave up his only hit when Ronnie Belliard doubled off the center field fence on a 3-1 pitch with one out in the fourth.
"We had a lead, so the last thing you want to do is walk guys, so I just basically just tried to throw it right down the middle and hope that he hit it right at somebody," Lowe said.
Lowe's highest pitch count this season was 121, so he could have extended it one more inning. But the 12-year veteran was happy to depart after 107 pitches, leaving the last three outs to the bullpen. Joe Beimel allowed a one-out single by Willie Harris in the ninth before rookie Cory Wade finished the combined two-hitter.
"Complete games are fantastic, but this isn't about trying to be heroes and pitching complete games. It's about trying to get us wins and be as strong as you can every time out," said Lowe, whose three complete games last season all were losses. "My next start is going to be a big one against Brandon Webb on Thursday, so I need to save those 15 or 20 pitches for them and be as fresh as I can, rather than go out there for the ninth tonight."
Perez faced the Dodgers for the first time since they traded him to Kansas City in July 2006, and the left-hander found himself behind 3-0 after just 16 pitches. Juan Pierre led off with a single and Kemp hit his 12th home run, extending his hitting streak to a career-best 13 games. Russell Martin followed with a double and scored on Garciaparra's sacrifice fly.
"I just wanted to go out there and have a great game and beat them, but it didn't happen," Perez said. "I warmed up very good, but as soon as I got into the game, I didn't have it. I don't know what went wrong. Every mistake I made, they were waiting for that pitch. If they keep playing that way, they might win the division."
The Dodgers made it 6-0 in the fourth. Garciaparra led off with his fifth homer on a 3-1 fastball, Angel Berroa doubled home a run and Lowe followed with an RBI single.
Garciaparra is hitting .315 with four homers and 14 RBIs in 17 games since returning to the lineup on July 4. He started at first base for the first time this season. Dodgers manager Joe Torre wanted to give James Loney a night off, but put him in for defense for the final two innings.
Perez was 45-40 with a 3.94 ERA in 120 starts for Los Angeles between 2002 and 2006. In his first season with the Dodgers, he threw a pair of one-hit shutouts and finished 15-10 with a 3.00 ERA and 155 strikeouts -- all career bests to this day. Since leaving them, he is 13-23 with a 5.20 ERA in 57 starts.
"I had a great time in Los Angeles, and it hurt me a lot when I left," Perez said. "There were some hard feelings, but I understand baseball is a business."
Casey Blake, acquired by the Dodgers from Cleveland on Saturday for a pair of minor leaguers, started at third base and was 2-for-3 with a double and a run scored. Blake, who was batting .234 through the end of May, is hitting .352 in 45 games since then with 29 RBIs. He is the fifth player to start at third base this season for Los Angeles.
When former Dodgers owner Walter O'Malley is inducted posthumously into the Baseball Hall of Fame on Sunday, he will join two other former team executives enshrined at Cooperstown -- Branch Rickey (1967) and Larry MacPhail (1978). Among the contingent representing the organization at O'Malley's induction will be Tommy Lasorda, longtime traveling secretary Bill DeLury and Spanish language broadcaster Jaime Jarrin. O'Malley's son, former Dodgers president and owner Peter O'Malley, will speak on his father's behalf. Walter O'Malley died in 1979. ... Dodgers bullpen coach Ken Howell has returned to work after being hospitalized with a staph infection that caused him to have the middle toe on his right foot amputated. ... Dodgers rookie 3B Blake DeWitt was optioned to Triple-A Las Vegas. He is batting just .200 in 40 games since then with six RBIs in 125 at-bats since being the NL rookie of the month for May. ... Loney is the only player to appear in all 103 games for the Dodgers.