A brilliant free-kick from Tony McMahon inflicted a first home defeat on manager Jimmy Floyd Hasselbaink as Bradford earned a hard-fought 1-0 victory at Northampton.A game of few chances was won by McMahon's fine strike in the 34th minute, sending Bradford up to third in League One and dropping the Cobblers to 20th.Hasselbaink had won his first two matches in charge at Sixfields, but after one point from two games on the road has now seen his side go three without a victory.The Bantams had two good chances in the first eight minutes but Nicky Law shot straight at Matt Ingram and then Dominic Poleon missed his kick from eight yards out.Charlie Wyke also tested Ingram, and the visitors eventually took the lead in controversial fashion when Brendan Moloney was deemed to have fouled Alex Gilliead 25 yards out and McMahon exquisitely curled the free-kick into the top corner.The second half was short on action as Bradford stood firm and soaked up plenty of Northampton pressure, with both Alex Revell and Marc Richards missing great late chances to pinch a point for the home side.