CHICAGO - David Robertson somehow had mostly flown under the radar this season, even in his role as Mariano Rivera's replacement.

He had been perfect in his first nine save opportunities as the heir to the game's greatest closer, allowing the spotlight to fall elsewhere.

Not Friday night.

Handed a one-run lead with two outs in the eighth inning, Robertson allowed a monstrous two-run homer to Adam Dunn on an 0-and-2 pitch with none out in the ninth, giving the White Sox a 6-5 walk-off win at U.S. Cellular Field.

"It's frustrating," said Robertson, who had allowed two earned runs in 122/3 innings (for a 1.42 ERA) before Friday night. "The team fought real hard today. We had a win there. We're three outs away and I let them down today. I didn't make enough quality pitches and cost us the game."

Making his third four-out save attempt since May 15, Robertson replaced Adam Warren in the eighth with two on and two outs and struck out Conor Gillaspie. But that would be the last out he'd get.

Dayan Viciedo led off the ninth with a single on an 0-and-2 pitch and Moises Sierra pinch ran for him. After Robertson got ahead of Dunn 0-and-2, he threw a fastball down the middle and the 6-6, 285-pound Dunn hit his eighth homer of the season and 448th of his career.

As soon as Dunn made contact, Robertson -- who wanted the pitch "down and away" -- clasped both hands behind his head, having no doubt about where the ball was headed.

"As soon as I heard it hit the bat, I knew it was gone," Robertson said. "That guy's got tremendous power. By the time I turned around and looked, I think it was out there in the seats."

Blowing saves, of course, is a part of every closer's life. Rivera blew one on occasion, too.

"It's a tough game, but our bullpen's been great all year and David's been perfect," Derek Jeter said. "Those things happen. You don't want them to happen but they do happen, and it will happen again at some point."

Brian McCann hit a three-run homer with two outs in the first inning against former Yankee Hector Noesi, an early indication that the Yankees might have the "bust-out" night offensively that Joe Girardi felt would be coming soon.

But Noesi, 0-4 with a 7.31 ERA coming in, shut down the Yankees for the next five innings and Hiroki Kuroda could not hold the lead. He allowed a two-run homer to Alexei Ramirez in the fifth that gave the White Sox a 4-3 lead.

Kuroda, who came in 1-1 with a 3.86 ERA in four starts this month after going 2-2 with a 5.28 ERA in five April starts, allowed four runs (two earned) and eight hits in 42/3 innings.

"We didn't help him,'' Girardi said, a reference to errors committed by Kelly Johnson at first and Brian Roberts at second that led to unearned runs. "We gave them extra outs."

Still, a run-scoring wild pitch and Jacoby Ellsbury's sacrifice fly gave the Yankees a 5-4 lead in the seventh, and the way things have been going with the bullpen, a victory seemed assured.

Before Robertson entered the game, Dellin Betances (11/3 scoreless innings) and Warren (12/3 scoreless innings) again were effective.

"We had the game where we wanted it, in Robby's hands," Girardi said.

And Robertson would like it there again soon.

"You're not going to have a good game every time," he said. "This one ended poorly for me, but I'm sure I'll get more opportunities. I'm not frustrated. I've blown games in the eighth and lost them for us, so this isn't my first time."