NEW YORK -- Johnny Damon put on a hitting display for the record books and finished it off in style.
His six hits matched a Yankees record, and tied the American League mark for a nine-inning game.
"It was pretty amazing. Pretty exhausting," Damon said.
New York overcame a pair of four-run deficits and a huge game by Kansas City's Jose Guillen, who hit a tiebreaking grand slam in the seventh and matched a club record with seven RBI.
After David DeJesus put the Royals ahead 11-10 with a homer on the first pitch from Mariano Rivera (2-1) in the ninth, Jorge Posada connected against Joakim Soria with one out in the bottom half to tie it.
With two down, Wilson Betemit walked and Melky Cabrera reached on an infield single. Damon pulled a 3-1 pitch from Soria (0-1) into the right-field corner for his sixth hit, setting a career high and equaling a Yankees record now accomplished three times.
"I have had a couple of opportunities, but I never got the sixth. It was a perfect time," Damon said.
Myril Hoag also went 6-for-6 for New York on June 6, 1934, at Boston, and Gerald Williams was 6-for-8 in a 15-inning game May 1, 1996, at Baltimore.
Omar Vizquel is the only player besides Damon to get six hits in a game at Yankee Stadium, going 6-for-7 with Cleveland on Aug. 31, 2004.
"All of the great players who have played here, it's pretty amazing that nobody's ever done it," Damon said.
After his first game-ending hit for the Yankees, Damon was mobbed by teammates at first base and got a big hug from Alex Rodriguez while waiting to do a television interview on the field. With the sellout crowd of 53,611 chanting his name, Damon popped out of the dugout for a smiling curtain call.
Damon finished with four RBI from the leadoff spot. His two-run single in the eighth off Ramon Ramirez tied it at 10.
"A couple of the pitches he hit weren't bad pitches," Royals manager Trey Hillman said. "It was one of those days that Johnny Damon was really hot and we weren't real sure where to throw him."
Damon doubled and scored in the first, then singled in the third, fourth and sixth. The outfielder had just shaved his lucky mustache, too, after an 0-for-5 night Friday snapped his 14-game hitting streak.
It was New York's second thrilling comeback in three days. Jason Giambi connected for a pinch-hit, two-run homer with two outs in the bottom of the ninth Thursday to beat Toronto 9-8. The Yankees fought back from a five-run hole in that one.
This time, Giambi and Rodriguez homered for the Yankees, who set a season high with 19 hits and improved to 3-27 when trailing after seven innings. New York has come from behind in eight of its past 10 victories.
"It was a special day," Posada said. "It was a hot one, and we kept on coming."
Guillen homered twice and threw out two base runners from right field, but somehow it wasn't enough for the slumping Royals -- who tagged Andy Pettitte for 10 runs in 6 2/3 innings.
Kansas City, which has lost 16 of 19 overall, dropped to 4-28 at Yankee Stadium since the start of the 2000 season.
"We gave it away three separate times," catcher John Buck said.
It was Soria's first blown save in 14 chances this year. He was Kansas City's seventh pitcher during a game that lasted 3 hours, 50 minutes, in 90-degree heat.
Joey Gathright tied it at 6 in the seventh with a bad-hop RBI single and Yankees manager Joe Girardi left Pettitte in to face the right-handed hitting Guillen with the bases loaded and two outs -- a curious move that backfired.
Guillen, who hit a two-run shot off Pettitte in the first and an RBI single in a three-run third, lofted the lefty's 111th and final pitch to left field for his fourth career slam and first since Sept. 9, 2002, with Cincinnati against Pittsburgh.
It was Kansas City's first grand slam since Ryan Shealy connected on Sept. 15, 2006, against Seattle. With seven RBI, Guillen also matched a franchise record accomplished 11 times, most recently by Mike Sweeney on July 22, 2004, at Detroit.
Rodriguez's long, two-run shot off Brett Tomko in the seventh cut it to 10-8.
"It was a pretty crazy game," Soria said.
Guillen was shaken up in the sixth when he fouled a ball off his left shin. He stayed down for a couple of minutes but remained in the game and grounded out. He departed in the seventh.
Plate umpire Jerry Layne was staggered by a foul bunt off his mask and left in the third inning. He has a mild concussion and was to be kept overnight at the hospital for observation, Yankees spokesman Jason Zillo said.
Second base ump Jim Wolf moved behind the plate, and the game was delayed for about 15 minutes before resuming with only three umpires.
- Chone Figgins of the Los Angeles Angels was the previous AL player to get six hits in a nine-inning game, on June 18 last year against Houston.
- The 10 runs allowed by Pettitte matched a career high.