The Orioles swept a three-game series against the Chicago White Sox, extended their American League East lead to nine games, and watched Wei-Yin Chen win his career high 13th game.

They also won their 39th game on the road, most in the American League. While they have a good record at home (34-26), they’re 13 games above .500 on the road (39-26).

The Orioles’ 4-3 win over the Chicago White Sox before 15,137 at U.S. Cellular Field was their fourth straight and they have three more games this weekend at Wrigley Field.

Why are the Orioles so good way from home?

“I don’t know. I really don’t. Maybe we like coming to the ballpark later, sleeping in. I don’t know. Maybe it’s the early wake-up call at home. Maybe it’s our wives. Just kidding! No, I don’t know. I really don’t,” Darren O’Day said. “But it’s a good quality to have because when we get down the stretch we’re going to play some important road games, and in the playoffs you obviously have to play on the road, so it’s a good quality to have.”

O’Day recorded two key outs, strikeouts of Jose Abreu and Avisail Garcia with two runners on in the eighth, and the Orioles clinging to a one-run lead.

“Those were two really tough hitters to go through,” manager Buck Showalter said.

Wei-Yin Chen pitched 7 1/3 innings and ran his record to 13-4. In 2012, he won 12 games. Chen became the second Orioles pitcher in three nights to record a career high in wins. Bud Norris won his 11th game on Monday night.