Top seed Serena Williams suffered a shock defeat to fellow American Madison Brengle in the second round of the WTA Auckland Classic on Wednesday to bring an abrupt end to her return to the court. In her first tournament since losing in the semi-finals of the US Open four months ago, Williams was bundled out 6-4, 6-7 , 6-4 by the world number 72 in a two-hour, 13-minute arm wrestle.