Sabathia went on to defeat the Orioles for the second time in six days, Raul Ibanez hit a go-ahead single in the fifth off Jason Hammel after former Baltimore high school star Mark Teixeira singled and swiped second in a rare steal. Diving second baseman Robert Andino just missed gloving Ibanez's hit.
Ichiro Suzuki added an RBI double off the right-center field wall in the sixth. Curtis Granderson boosted the lead to 3-0 with a second-deck solo homer against Troy Patton in the seventh.
Sabathia, who improved to 4-0 in his last eight postseason starts, didn't allow an extra-base hit. He struck out nine, walked two and matched his season high of 121 pitches.
"He didn't pitch all five, but it certainly felt like it, didn't it?" Showalter said.
Sabathia took a one-hit shutout into the eighth but allowed Matt Wieters' leadoff single and Manny Machado's walk. Mark Reynolds struck out, and Lew Ford — starting at DH in place of Jim Thome — hit an RBI single.
Andino hit a bouncer to the third-base side that Sabathia gloved, but Eric Chavez left third uncovered and Sabathia's throw to second was late, leaving the bases loaded. With David Robertson warming up in the New York bullpen, McLouth struck out on a changeup and Sabathia escaped when J.J. Hardy hit a slow three-hopper to shortstop that Jeter, playing on a sore left ankle, charged and gloved elegantly before throwing to first just in time.
Sabathia pitched a 1-2-3 ninth, finishing a 121-pitch effort as Wieters hit a comebacker. The Yankees ran out of their dugout to celebrate on the third-base side of the mound and the Orioles walked off slowly and somberly.
"It's been about as much fun as I have had in the big leagues watching how they play the game every day, the standard they held themselves to and the way they raised the bar in Baltimore with each other," said Showalter, who has not reached the LCS in 14 major league seasons.
New York won for the 12th time in 23 meetings between the teams in a matchup so close the Yankees outscored the Orioles 106-102. The teams were within one run of each other at the end of 46 of 52 innings in the division series. New York totaled just 16 runs in the five games and Baltimore 10, ending a dynamic six-week struggle. After 10 different nights in September, the rivals were tied for first.
"They are a very good club and they are a very resilient club," Girardi said. "People thought they were going to go away, they never went away."
NOTES: The crowd of 47,081 was the smallest in 18 postseason games at new Yankee Stadium, which opened in 2009. ... New York is 11-3 in the ALCS. ... The 26 runs were the fewest in a five-game postseason series since St. Louis (12) and Arizona (10) combined for 22 runs in the 2001 NLDS.