SAN FRANCISCO (AFP) — The postseason races went down to the wire on the final day of the season as San Francisco and Atlanta punched their playoff tickets and San Diego stumbled their way out of contention.

The Giants captured the NL West title by beating San Diego 3-0 as Jonathan Sanchez and five relief pitchers combined on a four-hit shutout Sunday.

Buster Posey put the exclamation point on the win with a lead-off homer in the eighth inning for the Giants who returned to the playoffs after a six-year hiatus.

"We nailed it," Giants outfielder Pat Burrell said. "It was looking like it was heading the wrong way. Our guys toughed it out."

San Francisco lost the first two games of the season-concluding series, but are now in the playoffs for the first time since 2003.

They'll play the wild-card Atlanta Braves on Thursday at AT&T Park in the playoff series opener with NL East winner Philadelphia squaring off against NL Central champion Cincinnati in the other first-round best-of-five series.

Tampa Bay clinched the AL East when the World Series champion New York Yankees lost at Boston 8-4.

That sent the Rays back home to open the playoffs against Texas, while the wild-card Yankees will start their best-of-five series at Minnesota.

The AL champ will face the National League winner in the best-of-seven championship World Series later this month.

The postseason starts Wednesday in Tampa. The banged-up Braves visit Tim Lincecum and the Giants on Thursday.

Giants ace pitcher Tim Lincecum is well rested and ready to go for game one against the Braves.

"We're probably not expected to do well," said Braves pitcher Tim Hudson.

Braves 69-year-old manager Bobby Cox, who is retiring, is in the postseason again. Cox's Braves went 4-3 against the Giants this year.

Cox guided Atlanta to 14 consecutive division titles from 1991-2005, but only one World Series championship during that run. He and the Braves are back in the postseason after a four-year absence.

The hapless Padres spoiled a chance to force a Monday playoff with the Giants at Petco Park to decide the West winner. The loser of that would have travelled to Atlanta to determine the wild card had there been a three-way tie.

When Padres Will Venable struck out swinging for the final out, Giants rookie catcher Posey ran out to closer Brian Wilson and they jumped together at the mound. The rest of the Giants mobbed them and crisp NL West champion shirts were quickly pulled on.

The San Francisco players then took a victory lap along the outfield warning track.

In the American League playoff race, the reigning World Series champion Yankees settled for a wild-card berth Sunday after losing to rival Boston in their regular-season finale.

The defeat left the Yankees at 95-67 while Tampa Bay defeated Kansas City 3-2 in 12 innings to finish at 96-66 to edge the Yankees by one game for the AL East division title.

"It took a little of the tension off," Rays manager Joe Maddon said. "We wanted to win this game. How 'bout that? Extra innings, on the road, didn't need to win. It tells you something about our ballclub."

The Yankees and Rays both had plenty of chances to pull away in the last week or two.

"It would be stupid to say it doesn't matter how you finish. We would have liked to get this thing done, but we didn't," Yankees pitcher Andy Pettitte said. "The bottom line is: We're the world champs until someone knocks us off."

It'll be CC Sabathia against the Twins' Francisco Liriano in game one, the first postseason game at new Target Field. The Yankees were 4-2 against Minnesota this year.

Jed Lowrie homered twice and J.D. Drew added another home run for the Red Sox while John Lackey struck out 10 Yankee batters in 7 2/3 innings, but Boston missed the playoffs for only the second time in eight years.

The Yankees had already clinched their 15th playoff appearance in 16 years but went only 29-30 in the last two months of the season.