Walsall ended MK Dons’ unbeaten start in League Two after a 1-0 win at Stadium MK.
Charlie Lakin scored the game’s only goal just after half time, with the visitors taking a fourth victory in their opening six games of the season.
Walsall settled quickly and had a fine opportunity when Lakin’s strike was tipped over by home goalkeeper Craig MacGillivray.
MK Dons struggled to create chances in the first half, but missed a great chance to take the lead just after half-time. Jack Sanders’ flick-on at a free-kick released Callum Paterson, who fired wide when one-on-one with Myles Roberts.
That miss proved costly when Walsall took the lead moments later. Lakin received Aaron Pressley’s pass in space on a counter and his firm strike beat MacGillivray via a deflection.
Roberts made a big stop to deny Nathaniel Mendez-Laing’s effort, with the keeper also denying Luke Offord’s header.
Roberts made a late save to deny Jonathan Leko but despite lots of second-half pressure, MK Dons could not find an equaliser.