The A’s biggest obstacle Sunday didn’t even involve the Texas Rangers.

In about a 20-minute span they had top starting pitcher Jarrod Parker scratched from their lineup along with Yoenis Cespedes arguably their most dangerous hitter.

That simply forced the A’s to invent a new way to frustrate the Texas Rangers. They plugged emergency starter Tommy Milone into the mix and the beat went on during a 5-1 victory that completed a three-game sweep for Oakland.

The A’s arrived in Arlington needing to hold down the fort and prevent Texas from taking a sizeable bite out of their division lead. They aimed higher and succeeded in a major way.

Oakland now leads the American League West by 6 ½ games over the Rangers and lowered its magic number for clinching the division to eight.

A key for the A’s in the series – getting off to a fast start. They scored in the first inning in each of the three games and put up two runs in the top of the first Sunday to put Texas in yet another hole. Incredibly the Rangers never held a lead over their entire six-game homestand.