NEW YORK -- Ryan Dempster had a simple explanation for what he needs to do better.
"You've got to execute pitches," Dempster said. "It's that simple. I have to do a better job of it."
Dempster was doing a superb job of that for two innings on Monday night, retiring six straight hitters on just 25 pitches while his offensive teammates staked him to a two-run lead. Then the Yankees scored five runs in the third inning and went on to an 8-2 victory at Yankee Stadium.
Nick Swisher's grand slam was the big hit in the third, and it's the first time that Dempster has allowed five runs in an inning this season. He ended up allowing eight runs in six-plus innings overall and is now 1-2 with an 8.31 ERA in three starts since being acquired from the Cubs at the Trade Deadline.
"In the first two innings he was down with everything," manager Ron Washington said. "Then they went up there in the next inning and they made him elevate. When he missed, they didn't miss. That team over there, you've got to execute. You don't execute, they make you pay. That's what they do. They're a veteran club, they know how to make adjustments and they know how to hit. You've got to keep it down."
The loss left the Rangers with a six-game lead in the American League West over the Athletics, who were off on Monday. They have lost nine of their last 13 games against the Yankees and are 23-45 against them during the regular season since 2004. They have lost nine of their last 10 regular-season games at Yankee Stadium.
The Rangers managed just two runs in nine innings against Yankees rookie right-hander David Phelps and veteran pitcher Derek Lowe, who was just signed on Monday after being released by the Indians. Phelps made one relief appearance against the Rangers in April, allowing three runs in 2 1/3 innings. On Monday night, he earned the victory by holding them to two runs in five innings.
The Rangers scored on him in each of the first two innings as seven of their first 14 hitters reached base on five hits, a walk and a hit batter. Nelson Cruz had an RBI single in the first and David Murphy led off the second with a home run. But Phelps also picked two runners off base.
"He had pretty good stuff, but we definitely could have scratched a few more runs across," Murphy said.
Phelps picked off Ian Kinsler at first base to end the second and then got Elvis Andrus at second in the third inning. The Rangers had runners on first and second, one out and Cruz at the plate when Andrus got nailed.
"It's not a good feeling for sure, especially in that situation," Andrus said. "I was a little too aggressive."
"Those are two big outs that he got, especially with the guys that always loom behind Kinsler and Andrus," Yankees manager Joe Girardi said. "These guys are extremely dangerous, and to be able to change innings because of that is really important. He does a great job of holding runners on. He's got a good pickoff move. They helped a lot."
That left the Rangers with a 2-0 lead before the Yankees went to work in the bottom of the third. Russell Martin and Raul Ibanez led off the rally with a pair of singles, Ichiro Suzuki bunted them to second and third, and Derek Jeter walked to load the bases.
"I still felt great," Dempster said. "I'll take singles, because you want to make them hit their way on. Russell Martin hit a good pitch and Ibanez hit a good pitch. Jeter worked a walk and then ..."
Swisher came to bat.
"For me, man, I'm just trying to put something in the air," Swisher said. "At least get one of them. That's all you're thinking in that spot."
Dempster had other ideas.
"In a situation like that, you're just trying to get a double play and get out it," Dempster said. "But you've got to make a pitch to get a double play or at least a fly ball and hold them to one run."
Instead, Dempster threw a 1-0 slider and Swisher hit it into the right-field seats.
"The ball hung up there and he made me pay for it," Dempster said.
That still gave the Yankees just a two-run lead. But they reloaded the bases on a walk to Robinson Cano, singles by Mark Teixeira and Eric Chavez. Curtis Granderson's sacrifice fly to center brought home the fifth run of the inning.
Chavez made it 6-2 with a sixth-inning home run and the Yankees scored two more in the seventh on a triple by Suzuki, a double by Jeter and a single by Swisher.
"Those tack-on runs hurt," Dempster said. "It just came down to executing pitches. Nothing more, nothing less. I paid for my mistakes."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.