"It's been really tough. It's been like a nightmare I can't wake up from," Hughes said. "It's like a battle every time, even if I have a good start. It's not easy. On a day like this, it's really disappointing."
Hughes permitted six hits in the brief outing and has now lost eight of his last 10 decisions since May 15. He has allowed five earned runs or more in five of those starts, but manager Joe Girardi was not yet prepared to say that Hughes' rotation spot is in jeopardy.
"He just didn't make pitches when he had to," Girardi said. "He got into some counts where he couldn't put people away today. It comes down to quality pitches, it really does. If you miss by a little bit in this league, you usually get hit."
As the Yankees braced for the expected arrival of embattled slugger Alex Rodriguez on Monday in Chicago, they were first confronted with a reminder of what might have been.
Ian Kennedy, their first-round Draft selection in 2006, made his San Diego debut and held his former club to two runs and four hits over 5 2/3 innings.
Kennedy was once envisioned as a piece of the Yankees' future, alongside Hughes and Joba Chamberlain, but Kennedy was dealt by the Yankees in a December 2009 three-team deal with the Tigers and D-backs that fitted Curtis Granderson for pinstripes.
"The adrenaline got the best of me later on, but early on I tried to control it," said Kennedy, who was acquired by the Padres from Arizona last week. "I started feeling it, trying to control it -- the first start against the team that drafted me. I was a lot into it."
Kennedy had little issue navigating New York's lineup, and San Diego built a 6-0 lead for him through four innings. Everth Cabrera drilled a two-run single and Mark Kotsay had a sacrifice fly in a three-run second inning, while Chris Denorfia and Kotsay each collected RBIs in the third inning to knock out Hughes.
"He has to make better pitches," Girardi said. "At times, we see him do it. It's just a consistency thing. That's what pitching is about."
Hughes said that he cannot be concerned about losing his spot in the rotation, since those decisions are out of his hands. He said that he will continue working with pitching coach Larry Rothschild, and though the results are not consistent in games, Hughes believes he has made progress in between starts.
"On the side, I feel pretty good. I feel like I'm making strides," Hughes said. "That's all I can really do, is just work on executing pitches and try to do that as much as possible. I felt pretty good out of the windup today. Unfortunately, I wasn't able to pitch out of it that much. I have to figure something out."
Chase Headley knocked a run-scoring single in the fourth off Yankees reliever Preston Claiborne. Kennedy silenced the Yankees until the sixth, as Granderson and Lyle Overbay connected for run-scoring singles that drew New York within four runs.
"Anytime you come to a new team, there's emotion and there's quite a bit of adrenaline, and at the end he sort of ran out of it a little bit," Padres manager Bud Black said. "I think he probably tired a little quicker than what you'll see in the future, that's what happened in the sixth."
Austin Romine hit his first Major League homer, a solo shot, off Dale Thayer in the seventh inning. The milestone ball was tossed into the stands by a Padres reliever but later retrieved by a member of the Yankees' security team.
On a day when the Yankees also learned that shortstop Derek Jeter is dealing with a Grade 1 right calf strain that could send him for a third stint on the disabled list this season, Girardi said that it was disappointing to leave town with two losses in what he viewed as a winnable series.
"It's frustrating," Girardi said. "We had a chance to win the series here and we didn't do it. But we've got to do it. If we want to play in October, we've got to do it."