The White Sox's latest enemy?

Themselves.

Enough offense to hold a lead against Indians ace Justin Masterson wasn't enough Monday night, as a baserunning gaffe by pinch runner Blake Tekotte and a throwing error by reliever Matt Thornton were the primary mistakes in a 3-2 loss that extended the Sox skid to four games.

"It's just one of those you keep shooting yourself in the foot," said manager Robin Ventura, whose direct answers spoke volumes about his level of disappointment. "You give major league teams opportunities, and they're going to take advantage.

"Until you clean it up, you're going to lose games. It's just that simple. It's not hard to figure out.''

What annoyed Ventura the most is that the Sox work thoroughly on fundamentals before batting practice and even as early as five hours before games.

"You work on all of it and do it," Ventura said. "You just have to execute it. Until we clean it up and get consistent with it, it's hard to win at this level when you keep giving opportunities away."

The troubles surfaced in the bottom of the seventh with the Sox holding a 2-1 lead against Masterson. Tekotte pinch-ran for Hector Gimenez, who was nailed on the left shin by a pitch, and was at second base with no outs.

But Tekotte drifted too far off second, and catcher Carlos Santana quickly threw to second to nail him for the first out.