Christian Roberts marked his Swindon debut with the winner over Oldham.
Roberts, a midweek signing from Bristol City, was left unmarked at the far post to sidefoot home from close range following Sammy Igoe's corner.
Swindon were good value for their victory, with Brian Howard twice denied by Latics's keeper Les Pogliacomi.
Scott Vernon struck the post for Oldham, while Igoe struck the woodwork at the other end as Swindon pressed for a second goal.
Swindon: Evans, O'Hanlon, Ifil, Nicholas, Mitchell,
Duke (McMaster 56), Hewlett, Igoe, Howard, Fallon, Roberts.
Subs Not Used: Book, Robinson, Heywood, Smith.
Booked: Mitchell, Howard.
Goals: Roberts 14.
Oldham: Pogliacomi, Holden, Daniel Hall, Haining, Lomax, Betsy,
Eyre, Lee (Winn 83), Eyres (Christopher Hall 71), Vernon,
Barlow (Griffin 71).
Subs Not Used: Mawson, Arber.
Booked: Eyre, Daniel Hall.
Ref: S Tomlin (E Sussex).