Bruce Chen was one out away from surviving the seventh when everything unraveled.
The Royals left-hander had matched Yankees counterpart CC Sabathia nearly pitch for pitch Friday night, and with Robinson Cano standing on first base and light-hitting Eduardo Nunez at the plate, it was almost a foregone conclusion that Chen would turn over a tie game to the bullpen.
That's when Nunez ripped a triple into the right-field corner.
Chris Stewart followed with an RBI double, and Derek Jeter delivered the knockout punch with a two-run homer to center field, giving the Yankees a 6-2 lead that stood up at the end.
"They are very good hitters. Right now Jeter is very hot," Chen said afterward. "I'm not saying he's not a good hitter, but like right now, he's on fire and hitting the ball well. I should have made better pitches and make sure I kept the ball down."
As bitter as the loss was for Kansas City, it was an uplifting night for the Yankees.
Mariano Rivera started it off by announcing before the game that he plans to return from a torn ACL and meniscus damage in his right knee rather than retire. It ended when David Robertson struck out the side in the ninth to give Sabathia (4-0) his fourth straight victory.
"CC steps up when we need it," Jeter said.
Jeter's leadoff single was his fifth hit in six at-bats in the series, and Mark Teixeira made it hurt when he pounded a 1-1 pitch from Chen (0-4) into the seats overlooking the Royals' bullpen in left field. It was the seventh time Teixeira had gone deep against him.
"You want to face the best. He's one of the best," Chen said. "Everything is a challenge. You welcome challenge. I want to keep getting better, so I can prove I can hang out with the best."
Kansas City answered in the bottom half of the first. Alex Gordon followed a base hit by Jarrod Dyson with an RBI double, and Francoeur's two-out double tied the game.
The Royals couldn't have known that's all the offense they would muster.
Sabathia retired 12 straight after a two-out double by Alcides Escobar in the second. Eric Hosmer broke up the streak with a two-out triple in the sixth that hit the wall just over Curtis Granderson's head — about two feet shy of clearing the center-field fence. Francoeur grounded out to end the inning with a whimper.
Sabathia also left a runner on third in the seventh, when Mike Moustakas doubled leading off and Chris Getz delivered a base hit. Escobar grounded into a double play to end that inning.
Sabathia allowed seven hits and struck out five without issuing a walk.
"I sitting over there during the course of the game, trying to figure out a better left-hander in the game today," Royals manager Ned Yost said. "I couldn't come up with one."
Chen matched him nearly inning-for-inning until the seventh.
Cano led off with a single, but all the real damage came with two outs. Eduardo Nunez hit a go-ahead triple into the right-field corner, and Chris Stewart followed with an RBI single.
Then the big blow from Jeter, a two-run shot over the center-field wall.
"I'm not surprised they left him in the game," Jeter said. "He was dealing."
Robertson finished up the game in a non-save situation. Yankees manager Joe Girardi said the right-hander would likely get the first chance to save games in place of Rivera, though he did not rule out former Rays closer Rafael Soriano also pitching the ninth.
"We wanted to give him a little experience in that sense, but he also hasn't worked in three or four days, too," Girardi said. "You like to keep your relievers going, so we thought we would get him in there."
Notes: The Yankees transferred RHP Michael Pineda to the 60-day DL and optioned RHP D.J. Mitchell to Triple-A. They recalled RHP Cody Eppley from the same squad and signed OF Dewayne Wise to a major league contract. ... Yankees OF Nick Swisher (hamstring) took BP on the field before the game and plans to run bases Saturday. ... Royals RHP Greg Holland (ribcage) will throw BP on Saturday and could leave for a rehab assignment Tuesday. ... RHP Hiroki Kuroda takes the mound Saturday for New York. RHP Felipe Paulino will make his season debut for Kansas City.