"He knows what he's doing," Florida manager Jack McKeon said. "He's an intelligent kid. Of all the kids we've brought up here, he's got a great work ethic. He's not of those guys who think, 'Hey, I'm in the big leagues, so I don't have to do anything.'"
Vargas (2-0), making just his sixth appearance since being called up from Double-A Carolina on July 14, threw six shutout innings before tiring in the seventh against the team that went into the game leading the league in runs, RBI, home runs and slugging percentage.
"We definitely couldn't get anything going," Reds manager Jerry Narron said. "He didn't look like a rookie pitcher. He changed speeds really well and located all of his pitches. He did not look like a young kid out there by any stretch."
The top five batters in Cincinnati's lineup went a combined 0-for-14 with a walk against him. Sean Casey was 0-for-3 and Ken Griffey Jr. twice fouled out to third while also going 0-for-3.
"My approach to Griffey was the same as it was to the other hitters -- get ahead and make them do the things I want them to do," Vargas said. "I threw one pitch to Griffey that I thought he was going to hit over the lights, but he fouled it off."
Vargas allowed three hits and one run with one walk and two strikeouts in 6 1/3 innings. He hit back-to-back batters with one out in the seventh, prompting McKeon -- the former Reds manager -- to replace him with Antonio Alfonseca.
Edwin Encarnacion drove in Cincinnati's only run by greeting Alfonseca with an RBI double.
Vargas, Florida's second-round pick in the 2004 draft, earned his first win in relief on July 27 against Pittsburgh.
"I wouldn't say it's getting easier," Vargas said. "I'm just more comfortable."
Cabrera wasted no time giving Florida a 2-0 lead, driving Eric Milton's 2-2 pitch 427 feet to left-center with Luis Castillo
on first base and two outs in the first inning. His 25th homer of the season and second in two games came two pitches after he took a borderline pitch for ball two.
"[Milton] tried to come in, but he left it out over the plate, and it looked like it ran right into his bat head," Narron said. "Great hitters don't miss pitches like that, and he's one of the better hitters in baseball."
Said Vargas: "It was great to have a two-run lead without throwing a pitch."
Gonzalez hit his fifth homer leading off the fifth, a 414-foot shot into the Reds bullpen in left-center that made it 3-0.
Milton (5-12) has yielded a major league-leading 33 homers this season. He is the first Reds pitcher to give up that many since Tom Browning allowed a club-record 36 in 1988.
"There were a lot of close pitches tonight," Milton said. "I didn't have my stuff, and I couldn't locate. I was a little erratic, but that was one of the tightest [strike] zones I've seen from an umpire this year."
Castillo and Paul Lo Duca added run-scoring doubles later in the inning to knock Milton out of the game. He lasted 4 2/3 innings, giving up five runs and five hits with four walks and four
Florida's Mike Lowell struck out swinging to lead off the second inning, snapping his career-high streak of consecutive at bats without striking out at 52. The streak was the longest in the majors this season. ... Lowell singled to lead off the eighth and snap his streak of consecutive hitless at-bats at 14. ... Felipe Lopez, Cincinnati's only representative on the All-Star team, has seven hits in his last 46 at-bats after going 0-for-4. ... Encarnacion, the Reds' rookie third baseman, went 1-for-4 and has two hits in his last 21 at bats ... Casey's hitting streak was snapped at nine games after he went 0-for-3 with a walk.