CHICAGO (AP) -- Zach Britton didn't need his best stuff to beat the White Sox's dismal offense.
Britton pitched six strong innings and Nick Markakis hit a three-run double to lead the Baltimore Orioles to a 6-4 victory Sunday.
Luke Scott and Mark Reynolds added solo home runs for Baltimore, which has won five of its last six. The Orioles will try to complete a four-game sweep Monday night.
Britton (5-1) allowed one run on five hits, struck out one and had three walks. The 23-year-old rookie left-hander lowered his ERA to 2.63. Britton was lifted after the sixth inning because of a callus that developed on his left middle finger.
"It's not a huge deal," said Britton, who had the callus removed. "I know Buck (Showalter) just said he wanted to kill it now before anything happens. It is something I get from the way I throw my sinker. It's kind of unique grip and it kind of give me a callus every now and then and it kind of happened today. They did a good job of taking it out. It's not really an issue, it's more of the weather, my hands are dry and that kind of stuff happens."
The White Sox did have opportunities, but they squandered 11 baserunners.
"They are waiting for something to happen to get them on the right track," Britton said. "I felt like I gave them some good chances to get back in the game, walking guys when we were ahead in the game and that is a big no-no and I did that today which is frustrating. I have some stuff I need to work on and hopefully I get that straighten out in my bullpen."
White Sox manager Ozzie Guillen was back in the dugout after being suspended two games for tweeting comments about an umpire earlier in the week. Before the game, Guillen said he agreed with the suspension.
"I think it was a very fair one," he said. "I think it was good for baseball and myself and the integrity of the game. I think if MLB made any good moves in the last 20 years, I think that is a good one because they don't make too many good moves, but they did this time."
Gavin Floyd (3-2) took the loss for Chicago, which got a pinch-hit homer from Adam Dunn in the eighth inning against reliever Jim Johnson . It was Dunn's first pinch-homer since April 20, 2003, at Montreal. It cut the Orioles' lead to 6-4.
Orioles closer Kevin Gregg allowed a leadoff walk to Alexei Ramirez and a single to Carlos Quentin . He rebounded when Paul Konerko took a 2-2 pitch for a strike. After Alex Rios took a third strike, he got into an argument with plate umpire Cory Blaser, who threw him out.
A.J. Pierzynski then grounded out to second to seal Gregg's fifth save of the season.
"We didn't have the big hit today," Guillen said. "At least we had somebody on base. That's the good sign. We make it interesting. We haven't been doing that for the last week and a half."
The White Sox (10-19) have lost 15 of 18 and have dropped five in a row overall, seven straight at home and finished April with a club-record 18 losses. Chicago also trails Cleveland by 10 games in the AL Central.
"Just because you go out and play hard doesn't mean you're going to win or get the hit," Konerko said. "But over the long haul, you've got to believe you will. I believe I will and I believe the team will."
Floyd allowed six runs on seven hits. He struck out five and walked two, and struggled through a five-run fifth inning.
After setting a Baltimore franchise rookie record for the most the wins in April, Britton didn't have many problems against the struggling White Sox offense. His only mistake came in the fifth inning when he gave up a solo homer to Brent Lillibridge .
Scott put the Orioles ahead with two-out solo shot in the fourth inning. It was his fifth of the season. Scott has homered three times in the last five games.
In the fifth inning, Reynolds tagged Floyd with a leadoff home run to left-center. Felix Pie followed with a triple off the center-field wall. Floyd then gave up back-to-back walks to load the bases and Markakis cleared them with a double to left-center. Markakis later scored on Scott's single to make it 6-0.
"We just felt he (Floyd) was in a pattern there," Markakis said. "He went away from his fastball, he threw a lot of cutters, slider and curveballs, you can almost go up there and sit on an offspeed pitch. The more pitches you can eliminate the easier to hit."
In the second inning with a runner on first and two outs, Orioles shortstop Robert Andino made a diving stop on Brent Morel 's ball and then got up to throw him out at first.
"It all comes back to having confidence in my defense," Britton said. "I didn't have my good stuff, but I just threw it over the plate and let them hit to the guys and let them make the plays." Johnson came on with the bases loaded and one out in the seventh inning. He got Quentin to pop out, then after walking Konerko to force in a run, got Rios to ground out to third to end the inning.
Notes: SS J.J. Hardy, on the 15-day DL with a left oblique, is scheduled to take batting practice in the cages on Monday and Tuesday then on the field Wednesday. ... White Sox left-handed hitters Pierzynski and Dunn were not in the starting lineup against Britton. ... The White Sox left 11 on.