ST. LOUIS (Ticker) -- Miguel Cairo turned an understudy role into a moment in the spotlight.

Cairo, filling in for the injured Scott Rolen, went 3-for-3 with two runs scored and two RBI as the St. Louis Cardinals posted a 6-3 triumph over the Arizona Diamondbacks, completing a three-game Division Series sweep of the defending world champions.

With Rolen likely sidelined until the World Series with a shoulder injury, Cairo - who delivered the decisive hit in Game Two - got the start Saturday. Despite hitting just .250 during the season, he justified manager Tony La Russa's faith.

Cairo had an RBI single in the second inning, was hit by a pitch and scored in the fourth, beat out an infield hit in the sixth and drove in an insurance run in the eighth with a double - the Cardinals' lone extra-base hit.

"When I got here, I saw my name in the lineup and I was surprised because sometimes (La Russa) goes with (Eli) Marrero in the outfield," Cairo said. "I just tried to relax, take it like another regular-season game and just go out there and have fun. And that's what I did."

"It's amazing that he was able to do as much as he did - three hits and a hit batsman where he ended up scoring," Cardinals starter Andy Benes said. "He's been good for us all year, he's a great player and he rose to the occasion tonight."

The win is the latest success in an emotionally trying season for the Cardinals, who overcame the June deaths of veteran righthander Darryl Kile and legendary broadcaster Jack Buck. St. Louis advanced to the League Championship Series for the second time in three years and avenged a heartbreaking loss to the Diamondbacks in last year's Division Series.

"They're the world champs and they're a class act all the way around," St. Louis second baseman Fernando Vina said. "They beat us last year and they crushed us. This year, we wanted to go out and win and prove something. And we did."

Last year, Arizona got by St. Louis in the first round and eventually outlasted the New York Yankees in seven games in the World Series. But Arizona was put in hole when aces Randy Johnson and Curt Schilling failed to win either of the first two games of this series and never got the offense going in the absence of injured slugger Luis Gonzalez.

"You have to congratulate the Cardinals, they outplayed us," Arizona first baseman Mark Grace said. "I can accept that. They were just too strong for us these three games."

St. Louis got 4 2/3 erratic innings from Benes, but its bullpen turned in a stellar effort as Jeff Fassero (2-0), Rick White, Steve Kline and Jason Isringhausen allowed two hits the rest of the way. Isringhausen picked up his second save of the series while Fassero appeared in all three games.

After Johnson took the loss in Game One and the offense deserted Schilling in Game Two, Brenly turned to Miguel Batista, who was masterful in beating St. Louis in Game Three last year. But Batista (0-1) was tagged for four runs and five hits in 3 2/3 innings.

David Dellucci, one of the players seeing increased time in the absence of Gonzalez, got Arizona off to a quick start with a two-run homer in the second.

"It was a spark for us, one that we hoped to capitalize off of," Dellucci said. "It was good for us to come out and score runs early, they've been tough to come by. To get two in the second inning felt pretty good. But they shut it down after that and they did some scoring of their own, and it's tough to keep plugging when a team answers right back."

St. Louis got back a run in the second on a two-out single by Cairo that scored Albert Pujols. Vina, who had nine hits in the series, got the Cardinals going in the third as he singled and scored on Pujols' two-out base hit.

St. Louis took the lead for good in the fourth. Batista hit Cairo with one out and Mike Matheny's single left runners on the corners. Benes got down a squeeze to produce the go-ahead run and Vina followed with an RBI single to make it 4-2.

After Rod Barajas homered with one out in the fifth for Arizona, Benes walked pinch hitter Chris Donnels and Junior Spivey around a foulout by Tony Womack.

La Russa pulled Benes and the move nearly backfired as Steve Finley greeted Fassero with a single to left. But Pujols made a strong throw to the plate to nail the slow-footed Donnels.

"I knew it was hit hard enough for him to make a play," Fassero said. "I turned around and I see the ball's there and he's about halfway down. I go, `OK we've got him. All Mike has to do is catch the ball.' From what I've seen behind the plate, he doesn't miss too many balls."

Arizona got a two-out single by Quinton McCracken in the sixth, but that was its last runner to reach.

The final straw for the Diamondbacks may have been closer Byung-Hyun Kim's performance in the eighth. Trying to keep the deficit at one run, Kim walked Pujols to open the inning but got the next two batters. Cairo came through with a two-strike double to extend St. Louis' lead to 5-3.

Matheny was intentionally walked and pinch hitter Kerry Robinson singled in Cairo. Kim, who has had trouble in big spots, walked Vina before retiring J.D. Drew on a flyout.

The Diamondbacks managed just six runs and hit .184 in the series. Their three starting pitchers lasted a total of 16 2/3 innings and surrendered 11 runs.

"It seems like every time we did something, they answered right back," Dellucci said. "We scored two runs early and the sign of a championship team is a team that comes back, shuts the door and scores runs of their own. And they did that. I commend them; they have a tremendous team and I think that's the team over there that's going to win the World Series."

"We just weren't able to find a groove," Spivey added. "You have to tip your hat to their pitching staff because they didn't really give us really anything good to hit. They need a great job of just keeping everyone off-balance and not giving in to our hitters."

St. Louis has swept three of its last four Division Series.

"I love this time of year," Vina said. "This is the time of year you get fired up. The excitement, the blood flowing, what it means to win games in October, and I get excited for it."