Roy Oswalt threw seven dominant innings, Raul Ibanez hit a grand slam and the Philadelphia Phillies clinched their fifth straight NL East title with a 9-2 victory over the St. Louis Cardinals on Saturday night.

In a season where nothing less than a World Series championship would be considered a success, there wasn't much of a party on the field. The Phillies had a been-there, done-that attitude toward winning the division last year, and this time was no different.

Players ran onto the diamond a bit faster than usual, but they simply exchanged handshakes, hugs and high-fives as if this was an ordinary game in April. They did at least put on shirts and hats proclaiming themselves division champs.

The fans didn't even scream all that loud, even when the Phillie Phanatic ran on the field with a big flag that said 2011.

Once they reached the clubhouse, however, the Phillies popped open the bubbly and celebrated their achievement.

With the Four Aces leading the way, the Phillies are seeking their third NL pennant in four years and second World Series title.

They've taken care of the first step. Now they'll use the 12 remaining games to get ready for the postseason. It's still uncertain who the Phillies will face in the best-of-five first round when the NL playoffs begin Oct. 1.

The major league-leading Phillies (98-52) are four wins away from setting a single-season club record.

Oswalt (8-9) allowed no runs and five hits, striking out seven. Brad Lidge got one out in the eighth after Michael Stutes ran into trouble, and Ryan Madson finished with a seven-run cushion.

St. Louis fell 4 1/2 games behind Atlanta in the wild-card race. They had won eight of nine to narrow the gap from 8 1/2 back on Sept. 6.

Cardinals starter Jake Westbrook (12-9) allowed one earned run and five hits in 3 1-3 innings. He's given up two earned runs or less in 11 of his 16 road starts this season, but fell to 8-4 away from home.

Oswalt, Philadelphia's best pitcher down the stretch last year after coming over from Houston in a trade on July 29, left spring training as the No. 3 starter behind Roy Halladay and Cliff Lee. But he struggled after starting 3-0, and a back injury forced him to the disabled twice.

The three-time All-Star was vintage Oswalt against the Cardinals. His fastball reached 94 mph a few times, and he had a nasty curveball.

Oswalt struck out Skip Schumaker on a 76 mph curve to leave two runners on in the seventh. All of his Ks came on swings.

Stutes nearly blew a 3-0 lead in the eighth after getting the first two outs. Four straight singles by John Jay, Albert Pujols, Lance Berkman and David Freese got the Cardinals within 3-2.

But Lidge came in and retired Allen Craig on a grounder to second on his first pitch to end the inning.

The Phillies then blew it open with six unearned runs in the eighth. Carlos Ruiz reached second when his grounder skipped past third baseman Daniel Descalso for an error. Ruiz went to third on Jimmy Rollins' one-out single and scored on Shane Victorino's single up the middle.

After Chase Utley was hit by a pitch, Ryan Howard struck out.

Octavio Dotel entered and Hunter Pence hustled out an infield single to shortstop Rafael Furcal to drive in another run. Ibanez then hit his slam to right to put it away.

Pence gave the Phillies a 1-0 lead on an RBI double in the first. An error by Furcal helped the Phillies add a run in the fourth. Placido Polanco led off with a walk. Oswalt sacrificed with one out and Furcal dropped the throw to second. Rollins followed with a single to load the bases. Victorino walked to force in Polanco to make it 2-0.

That ended Westbrook's night.

Arthur Rhodes came in and retired Utley on a shallow fly and Howard on a grounder.

Victorino hit a solo homer off Kyle McClellan in the sixth. He's been slumping lately, batting just .163 (14 for 86) in his previous 21 games.

Oswalt likely will be the fourth starter in the postseason after Halladay, Lee and Cole Hamels. Rookie Vance Worley would go to the bullpen, despite an 11-2 record.